Well, I DO have a medical degree, and I'm a psychiatrist, so...
Well, for starters, most you seem to be experiencing ilusions, that happens when your mind change some thing about the things you perceive with your senses (as opposed to an hallucination, wich is the creation of a brand new sensation, from thin air). But anyway, the sound thing MIGH be tinnitus, like someone said, or hallucination. But the chance for schizophrenia,right now, seems low. I would guess it's something organic (I mean, something very physical affeecting your brain, wich could be a tumor, but also the effect of some drug or poison or maybe convulsions, wich is a good bet, actually, because it seems to be cronic, you haven't died yet-I hope- and it comes and goes.).
So my suggestion: go to a neurologyst first. It may be a simple thing, and fully treatable, if you do it right.
Hope that helps, and I would love to hear from you again.