I had the exact same scenario! Just a few years before your issue, I fell and landed on my right hand, straining my wrist. It wasn’t broken, but it was really sore and months later it still hurt just as badly, so I went to a doctor. He said the tendons and the sheath they go through were likely inflamed, and all my mousing (both work and home) was probably keeping it inflamed. I switched to the evoluent at work and a Logitech thumb ball at home, and two weeks later I was fine.