When I had one I went to a hand specialist. First he had me massage it several times a day to see if the build up in the tendon sheath would go down. It was sometimes painful, but I was able to arrest it that way for a while. After trying this method several times and having the lump shrink then regrow again over the period of a year the doctor decided to try a method in which the lump is pierced with a surgical needle. This did not help sufficiently. My last resort was to have it surgically removed.
My husband also had one. We were both professional drivers and gripped a steering wheel constantly. He did not go to a doctor. He did experience pain for about eighteen months, but his finally went away on its own.
It is my understanding that switching activity will not necessarily help. The build up in the tendon sheath would need to be massaged and you should also at least see a physician. You do not need to follow through with any procedure suggested, and if you have insurance, most companies prefer non surgical methods be explored initially any way.