Tinnitus is usually what it is called. It isn't exactly normal, but it isn't dangerous. It can be very annoying.Asprin and other salicylates like in Pepto Bismol can cause it. Usually I have it worse when I take those and hardly at all when I don't. Some people have it all the time regardless of medications.http://www.nlm.nih.gov/medlineplus/tinnitus.html