I am sorry that you have a pain disorder. Working with clay is a very good idea. Not only will it help your hands and fingers but also diverts your attention from the pain plus boots your creative spirit! Good luck!
Glad you found polymer clay and I think you will enjoy it. I have chronic pain too and some days I can be creative and some days not so much. But it is a great distraction on the good days! I started with clay just out of college and was looking for a hobby that was far from studying medicine. All these years later I still love it!