It is called MES Musical Ear Syndrome. You could have had damage to your ear due to listing to high frequency music. What has happen is you have some damage and your brain continues to poll looking for sounds it once heard. I would suggest you see an audiologist-a clinic that sells hearing aids they will test you at no charge. I spend thousands of $ at Baylor Univ. in Houston, Tex. to find out what caused mine. It can drive you crazy at first. But you learn to tune it out after a while. But, to prevent any furthur damage to your hearing. Do not put this off. I am nearly deaf at this point. A lot of factors can also cause hearing loss, certain toxic medications, innter ear infections. You may not realize this is the beginning of hearing loss. As this is how is begins. Trust me I know I have been there. And if you are taking any medications ANY be certain that they are not a contributing factor to your problem. You can go on line and find out there are over 300 meds that can contribute to this loss. 
Good Luck! And hope this helps.I will be happy to help you find the material if you can not locate it. Also, I forgot to mention, you may have had a viral infection as sometime or another and it can lay dormaint for years and at some point and time attact the lowest immune part of your body.Which in your case could be your ear/nerve etc. It gets very in depth. I have studied at length and found answers on my own that 4 different Drs. gave me 4 different answers. Hope this will help you get started. And hopefully you do not have hearing loss. But, if you do-do what you can to prevent it now, the earlier the better. Do you have any veritigo with this? Sometimes that can also be a signal that something is going on. There is so much. Hope I can help!
