I'm sixteen (yeah, a baby still compared to many of you...please don't dismiss me straight off *grins*), live in the UK, and I'm a classical soprano. About two years ago, I started experiencing a double tone on certain notes in the upper middle section of my voice, which I covered up by using all sorts of dreadful techniques which my teacher at the time didn't pick up on, and which probably only compounded the problem. Eventually, it got so bad that I couldn't sing.
It turns out I have something called muscular diplophonia, a combination of lots and lots of bad techniques I was taught at the very beginning (eight years' worth) which has led to a number of the muscles involved in singing becoming incredibly screwed up, especially my jaw (which ended up being agony when I sang) and the root of my tongue. The sound gets completely destroyed by a kind of rattle as the two harmonics fight against each other. Nasty. I now have to redevelop these muscles in a totally different way, which is going to take a long time. Apparently it might have happened anyway, but the poor teaching aggravated it.
I've switched teachers at long last, and I'm now studying under a truly incredible lady who is completely revising my technique (and has been the most amazing emotional support through all this too). It's crazy how different everything feels - I'm effectively starting from scratch and it's scary. At the beginning of the summer I couldn't vocalize without the diplophonia kicking in and I've never been so depressed in my life. I'd previously been practising an hour a day and suddenly I couldn't even sing a scale. I wallowed in self-pity and I shouldn't have. But I'm over it now, working like stink, and beginning to make some progress, which is terribly exciting, though I've got a long long long road ahead of me yet.
Although I feel I maybe shouldn't strictly be in this community, I've been reading the posts here and they helped me a lot when I was really low. It is true that nobody but a musician understands when something like this happens to you. I have been lucky in that this is something I can control and get rid of systematically, and I so admire the strength and fortitude of those musicians in this community whose injuries are more severe and more difficult to treat than my own.
My best wishes to every one of you.