Tinnitus is literally ringing in the ears. Any kind of sound really, that cannot be heard by anyone else. It can vary from very mild to distressingly loud. It can be caused by loud noise exposure, taking of certain drugs, some illness or infection. Sometimes also a muscular reaction as in whiplash or other neck injury.
Many people find relief in different ways, others become accustomed to it.
There is as yet no absolute cure. But the medical profession is working on it. If you doctor or ENT specialist tells you to live with it, please contact your nearest Tinnitus Association for support. There is one in most countries. Do a web search on Tinnitus and you will find many more references on the subject.