I run one machine 80% or more of the time. My left hand, travel function, has been giving me much grief this year, especially the thumb. I kept thinking that I must have wrenched it back or something else. Maybe it is the shift wheel. I've been trying a wrist/thumb brace which help somewhat but is not the answer. The brace helps keep the thumb from moving out of place and provides compression. Doctor said arthritis - I say Bayer or equivalent.
Trying some time off right now but lifting G&T's can be strenuous while laid back. Stupid thumb still hurts. CBD rub does little but if I am having a bad day, Wood Lock Oil usually calms things down for a few hours at a time. Wong Tu Yick brand is what I purchase, usually through Ebay. My 1st wife (Chinese/Thai) turned me on to that stuff. Most Asian markets sell it. Think of liquid aspirin for your joints and aches. I keep a bottle in every truck and on my road pack. For me, it works and it works well most of the time but not always. A $10-$15 dollar bottle that lasts for months is cheaper than any doctor's office.
Pain is just part of life and it let's us know we are still in the fight. When I can no longer stand the pain, surgery is the next option but only when absolutely required. It was the right choice for the bone spurs on my big toes when nothing else helped and it got beyond toleration. Meanwhile, as my orthopedic surgeon told me, "You can take as much aspirin as you want to but if your ears start ringing, back off on the dosage a bit." Thanks, Doc, but three at a time works well for me and anything less is useless.