Shivānand Paris Howard

I don't know what it is.
But I'll tell you the general principle for all meditation. Just keep focused on the meditation and let whatever sensations  / experiences you have be. They will come, whatever is gonna happen will happen, and then they will go. I have found that the the body has energy channels which have blockages, these blockages become opened up *automatically* during meditation. During the process of them opening up, we experience sensations. But these sensations are not the goal of the path, but rather side effects of unblocking. Hence the instruction to stay focused on your meditation. 
Generally, my feeling is if something happens that might be a health issue we should get it checked out. In kaljug most people don't have a great avastha so stuff that comes up is usually health related rather than spiritual advancement. BUT, keep in mind that sometimes disease is buried deep, and as our body gets cleaned out, we experience colds etc which is garbage coming out of the body. So it's actually a good thing. 
Finally, if you still are unsure, go meet a sant. The internet cannot give you an accurate diagnosis but a sant who has a high avastha can probably help guide you further as needed. If you let us know which city you live near, we might be able to guide you to a sant. 

Good Q&A

Q. I have read that it is best to receive a personal mantra from a teacher rather than choosing one for oneself. Is this true?

A. Receiving a personal mantra from a teacher simply means receiving direct guidance from that teacher. It saves you time and it keeps you free from doubts regarding the validity of the mantra. But if you have some doubt about the teacher, then receiving a mantra from that teacher is worse than choosing one from a book.

Most seekers have very little knowledge of mantras. All they know is that a mantra is a potent sacred sound and that it has the power to guide the mind inward. With this much knowledge, people decide to find a mantra. In my interactions with students, I have learned that a large number of such seekers are not very sure about what they believe about mantra. They come to me for a mantra. I give them the one I think best, then they verify that mantra by reading books, surfing the Web, or talking to other teachers. Then they come back to me to share their discoveries: “I’m confused,” they say. “I met a teacher from India who told me I should practice some other mantra and I don’t know who I should listen to,” or “The meaning you told me for my mantra is not the same as the meaning I found in a dictionary,” or “I came across a mantra that I really like. Can I practice with that one instead of with the one you gave me?” In such situations, I hear quite clearly what that person is really asking—he’s asking, “Can I trust you?”

What that student doesn’t understand is that he doesn’t have trust in his own knowledge. His discovery regarding mantras and the teacher is still demanding verification. The vacuum can be filled only by gaining a deeper understanding of the dynamics of mantra, the illuminating energy it contains, its source, the process of transmission, the prerequisites for receiving and retaining a mantra, and the proper method of imbibing it. For every science there is a definite course curriculum and methodology for studying it. And the study of every science demands perseverance, patience, and discipline. But in relation to mantra science and its practice, we don’t feel that sustained perseverance or discipline is really necessary.

So it is necessary that you receive a mantra from a competent, honest, and disciplined teacher. A true teacher will ensure that you cultivate perseverance and discipline, for without it the mere practice of mantra will not bear the desired fruit. If you don’t believe in the value of perseverance and self-discipline, then choose a mantra from a book or simply log on to the Internet.

Q. But what if an authentic teacher is not available?

A. Don’t worry about finding an authentic teacher. Start with anybody who seems to be honest and sensitive. Your own desire to learn more about yourself, and the mantra’s role in this exploration, will help you discover the next level of teacher. Practice is the key to your personal growth. Prepare yourself, and you will always find what you need. Without that preparation, even if you happen to meet an advanced master, the two of you will not be able to communicate. Despite your best efforts you could not convince a university professor to come and teach you graduate-level courses when your mind is ready only to learn through the poems of Dr. Seuss. And even if you did, either he would have to come down to your level and teach only that which you can comprehend, or he would have to wait until you grow much nearer to his level so you can study with him the subject he is so well qualified to teach. Your own growth will guide you to the right kind of institutions, traditions, teachers, and adepts.

I have been playing with the tones since I watched those videos. For a long time now I was unable to hear anything but have been increasing my simran throughout the day trying to get back into the swing of things.
So I tried the technique that is described in those videos of focusing on the right ear which is my dominant side. It is the side that in the past I have heard stuff from before.
After a few minutes low and behold the high pitch tone appeared which I recognised. So I put my dhyan on it and slowly by slowly the intensity increased. Not to something I couldn't handle but much louder than the initial ringing you hear. I have never heard it that loud before. So I kept my attention on it for some minutes until it felt like my whole right side of my brain was resonating with the tone. It was no longer localised to my ear. To say I was surprised by the sensation was an understatement. So after that I decided to direct my surti towards the left ear whilst still listening to the sound. The resonating sound changed into a vertical bar like sensation and it slowly starting moving across my head to the left side. Shortly after that it felt like it had moved to the left side of my head it felt like the left side had been lit with by something and my left side also started ringing a similar tone. After a while the tones split and I could not contain my excitement and now for the first time I was hearing two sounds in the head simultaneously, which became quite loud the more attention I gave them.
Slowly as I tried to keep some kind of lock on both sounds in the left and right, they would merge for brief periods and you could feel a vertical bar like sensation of sound running between the eyes going upwards into the forehead. For the first time in my life I may have had glimpse of what it is like to hear the sound in the trikuti region. As before it was always localised to my right ride.
Please note, that I have not got the foggiest idea of what I'm playing with here, but whatever it is, something is definitely resonating more profoundly than a high pitch sound that starts in the beginning of the ear drum. But it is definitely not localised to my ear drum anymore.
Over the next couple of days, whenever I would look for the sound, it quickly appears on the right. Sometimes it now starts off as the sound of crickets in the night which slowly turns into the high frequency sound which then increases in volume. When you stop giving it attention then it disappears. However it now turns on randomly during the day on either side as I carry on my job and I am more aware when it does. If I am able to close my eyes and devote attention to it, then the volume increases and you get a type of sensation that your brain in your head is resonating with this sound. Is it intoxicating? Not yet. It takes a great deal of concentration to be able to keep an lock on it. I have heard and read that next stage after japna begins with dhyan avasta. I now appreciate it more when they say first learn to concentrate on the gurmantar and develop stamina in a thoughtless still state. Because when you are just trying to focus on a sound, it is much more difficult to maintain unless your foundation is strong, and you definitely notice your monkey mind taking random thoughts which can become very annoying when your trying to concentrate on something and surrender to it.
During the day I'm practising on the gurmantar a lot more. Then in the night when the house is quiet and all have gone to bed, I try and focus on the sounds.
I am also noticing during the day when my air is balanced in both nostrils. You can feel the flow in the trikuti between the eyes really easily.
Whatever changes may be happening in my surti I am definitely feeling more inwardly aware of subtle changes in my head and hearing is becoming more inwardly sensitive.
Waheguru

Read this post on Facebook. Enlightening read.
 
ANHAD SABAD
Anhad means continuous or nonstop. Sabad in Gurbani means the utterance of God. So Anhad Sabad means Divine Utterance which is still going on in the universe. It is not an utterance in the physical world where sound is produced by striking two material parts which dies as the energy that produced it is used up fighting the resistance of the media in which it travels. Anhad Sabad started in sunn, the materially void infinite space and is still going in sunn which encloses the whole universe: "Antar sunnun bahar sunnum tribhavan sunmusnum" p-943. It is this Sabad that created the universe:"Ek kwaa-ay te sab hoaa” p-1002" and it is with this Sabad that it is destroyed and created again:
"Utpat parlo sabday hovay. Sabday he phir opat hao-vay" p-117.
God is fully expressed in Anhad Sabad and it is also called Naam in Gurbani. Naam carries in it Divine Hukam/ Will, Divine Plan of creation, preservation and destruction, Divine Intelligence/ Wisdom/ Consciousness, Divine Laws and everything what God is. It created everything and is in everything:
"Jeta keeta teta Naaon. Vin Naavain naheen ko thaaon” p-4.
Naam or Anhad Sabad stays in every creation of God as Soul. So God extends into us as Sabad or Naam. Guru Nanak calls this Sabad as His Guru: “Sabad Guru surat dhun chela” p-943. 

It is to this Sabad, Gurbani is advising us to connect to  hear our Creator or Father and it is with this Sabad that we link with Naam which cleans our mind and we can connect with God Himself. Without this Sabad everybody is in spiritual darkness and Sabad enlightens the mind:
"Jeean andar jeeo Sabad hai jit Sauh milaava ho-ay.
Bin Sabday jag anher hai Sabdey pargat ho-ay." p-1250
This Sabad can be heard by taking our consciousness inside where it resides. The only way to do it is to silence our mind form its thoughts of the physical world or Maya. Naam Jpana is means to do that. This is done by cyclic utterance of Gurmantar and listen to it attentively till our surti is lost into the chant of it and we disconnect from our thoughts and land into sunn or mentally quiet state where Naam or Sabad reside. Even a short experience in that state is very relaxing and peaceful. If practiced in the company of experienced practitioners one will soon start hearing the Anhad Sabad in your ears (can be mistaken for tinnitus problem). The sounds generally heard are: ringing of bells, flute, chirping of birds in the morning, sounds of crickets in nature in the evening, rebab, sitar, drums, your own heart beat etc. 
When these sounds are heard in sunn state it is direct link to Sabad or Naam. It is then that our mind start getting cleansed up of dirt of Maya and getting closer to higher spiritual stages. We are advised to hear these Sabads:
"Mun dhovo Sabad laago Har sio raho chit laa-ay." p-919
As the mind gets further cleansing by regular Japna, it will start hearing Sehaj Dhun- a high frequency sharp low volume note which goes on all the time. This happens when mind reaches third sunn or dasam duaar or doorway to enter divine mansion. At that point all other nine doors of the body are closed and the tenth one is reached where Anhad Sabad goes on day and night and is heard by following the Guru's advise:
"Nau dar thaakay dhavat raha-ay. Dasvain nij ghar vaasa paa-ay.
Othay Anhad Sabad vajay din raatee. Gurrnatee Sabad sunaavania." p-124
When time comes for union with God Anhad Sabad changes to Toor (sound of long horn played outside Gurdwaras and temples) "Binvant Nanak Gur charan laagay vaajay Anhad Tooray"p-917, followed by Naad, a loud low frequency humming sound before you are let into Sach Ghar or Divine Mansion: "Anahad Banee Naad vjaaia p-375".  When mind makes entry into Sach Ghar, Anhad Sabad changes to Panch Shabad which welcomes the child of God to His House; who is the Emperor of the entire universe:
"Vaajay panch Shabad tit ghar subhaagay" p-917.
Mind then is fully awakened to its spiritual self by the Sabad.
"Dhun upjee Sabad jgaaia." p-1039
Free from bondage of Maya, mind sees nothing but Parkaash or Divine Light/ Jot and finally meets Beloved Lord:
"Pargati Jot milay Ram Piaray." p-375
Even  Gurbani reaches the Gurus through Sabads. They translate the meaning of Sabad into local language for people to understand it and practice on it. God's language is not Punjabi but Sabads the meaning of which only the Gurmukhs understand it:
"Sabde upjay amrit bani Gurmukh aakh vkhaavania:"
 

Bro, is there a reason you want to hear the naads? Why not ignore them and keep reading more and more Gurbani?
 
Bhul chuk maaf

Because Gurbani teaches you to search for the Shabad Guru (Naad) within.

Cool. This is part of the Anhad Naad. It is the sound of silence. It normally arises from an intense presence of silence.

When you become silent in the mind and when it is silent outside, then you will hear this. But it will start to go away as your mind becomes noisy and as your outside environment becomes noisy. You will start hearing those sounds instead.
It is not always necessarily connected to outside noises or mental noise but it often is. It is often related to silence.
Sometimes you will randomly hear it, even when the mind is not silent or environment is not silent, when you do just become silent and listen to silence.
This sound is a Sign to remain silent.