I'm guessing you did a lot of practising as well as performing.
Did you have any arm issues before this acute injury?
What instrument is it? just curious..
Are you taking time off from that activity now?

I don't know how you feel about chiropractic ( expert, highly skilled etc) of course.
But I will say I lucked out finding the one I went to, he helped me the most and much quicker than PT. I had been to 10 PTs, of varying skill levels, only 2 really stood out, one was a teacher of PT, and one was after I had learned a lot about TOS myself, so I kind of guided him by sharing what the other PT did..(top rib mobilisation).
But chiropractic might be needed at first , " if your foundation is crooked you can't have a strong house"... that is kind of my way to explain it..

First I suggest you explore our TOS sticky threads and learn as much as you can.
http://neurotalk.psychcentral.com/thread84.html
http://neurotalk.psychcentral.com/thread125577.html
helpful passive posture ideas-
http://neurotalk.psychcentral.com/album.php?albumid=422

Then use the search tool to find specific things, perhaps chiropractor, therapy, posture, state/city etc. searches here require 4 letters/numbers.

If you can find a really good DC or advanced PT locally, that is in the healer category.. IE uses many techniques and modalities , what ever is needed to help you heal & improve.. but no weird gimmicks or set plan of treatment.. they have to adjust to what improves/helps you and not any rigid plan they set. No weights, hand bikes, etc at all until pain is way down... or maybe never..