I’m not qualified to diagnose your problem, although I have also experienced pain in my thumbs from time to time. There was a period a couple years ago when my left thumb hurt constantly, even when I wasn’t playing drums, so I made an appointment with my doctor to try to get to the bottom of it. He said that I had mild arthritis and suggested that I simply take ibuprofen, which actually did help. Eventually, the pain seemed to subside and I stopped taking pain relievers. It still does flare up every once in a while, but has never been as bad as it was during those couple weeks of nonstop pain.
Here’s an article about thumb pain written by our columnist Luga Podesta M.D.:
If the pain continues, I will be glad to ask Luga to respond to you on in the Forum, although I suspect he would need more info. But the best thing you can do is to go to your doctor and let him or her inspect it in person.