This year I've started to get a lot of stiffness and some pain in my left hand fingers. Not yet 50! Had a test for rheumatoid arthritis, but fortunately that came back clear. Got cortisone shots, which helped, but only for 3 months. Reading this thread, I'm wondering if it could be early osteoarthritis. Along with that, my left pinkie has developed "trigger finger", which was at first annoying, and now really painful (in addition to not working properly.) And to make things even worse (!!), after badly slicing through my left thumb tendon last year and reconstructive surgery, I don't have full mobility in the thumb (no more thumb over the neck chords. )
I'm going to get surgery on the trigger finger shortly, but I'm really starting to worry about my future playing guitar. I can't imagine what it would be like if I ever have to stop playing .
I didn't start playing until a little over a year ago...at 50. So playing with all the aches and pains is just part of it for me. I pop an Advil or two and get to it. Whatever you do...DON'T QUIT! Playing several times a day has been the best therapy for me! Snuggled up with my guitar is my happy place