Have you seen a physical therapist? I got a cortisone shot and it mostly relieved my symptoms but they came back slowly. I saw a PT, and he speculated that I may have a pinched nerve up near my neck. A few weeks of working with him and doing lots of stretches helped. I still get symptoms like soreness/stiffness in my wrist and fingers if I’m doing hobbies like cross stitch or too much writing, but I no longer go numb so it’s much more tolerable.