I'm suffering from chronic repetitive stress-related pain in my hands, in what I can best determine is my abductor pollicis brevis muscle. It is brought on by everything from writing to turning valves to cello playing to rock climbing. It most closely resembles the pain of a cramp, and when exacerbated by intense usage during rock climbing, eventually makes me unable to grasp holds.
History, and notes:
The pain first showed up about 10 years ago when I was playing cello regularly (2+ hours a day). Minor at first, the pain became more immediate and more intense during manual activities such as cello playing and writing.
Eventually, I decided to take 3 months off cello to rest, and met with a performance therapist who said he was unfamiliar with the particular symptom, but who recommended I see a PT. I did so for a few months, twice a week, and he variously stretched my thumb, taught me techniques to avoid using the muscles while writing, and applied an ultrasound to the affected area. The last treatment caused extreme pain of the same sort I experienced while playing. I stretched for months, and wore hand braces.
Long story short, the PT didn't work, so I largely gave up playing cello, and the pain decreased (but didn't disappear) until I started rock climbing last year.
My reading online seems to suggest this may be brought on by electrolyte imbalances, or improper circulation. The first seems possible, though I've been unable to remedy the pain much by drinking Gatorade instead of water (I hydrate constantly). The second seems likely, since I find it hard to maintain warmth in my hands during the winter. Posts online seem to discount the idea that my 16 years of vegetarianism are directly causing this, though I have considered this possibility.
At this point, I'm hoping someone has experienced or knows of this sort of pain, and might be able to identify an underlying cause, and suggest remedies. Any help is greatly appreciated!