To answer that question I went to a nerve doctor had the carpel tunnel surgery discovered my middle finger would not not lie flat doctor snipped the nerve sooo much better part of arthritis and osteoarthritis....

Yes I do have

Have you had any procedures done to your hand? Do you have arthritis?

Thanks your very helpful

Literally so many possible causes you should see your Doctor and after a couple of months that should tell you whatever it is it is chronic and needs looking at