It is fashionable to refer to any arm or hand problem as carpal tunnel syndrome, but there are many other conditions out there, some from static stress rather than repetitive stress. You need a pro to tell you which you have and what to do about it. Show them how you play your instrument if they are willing. Don't hesitate to adjust or change your instrument set up, once you understand what is causing problems. The traditional set up is not sacred, and you are an individual.
Teachers are often helpful here.
Finally, let me add my voice to the chorus that says that if the pain is serious or persistent, delay in seeking medical help costs you double. The longer you wait, the worse your injury may get, and the longer the recovery time may be. Orthopedic problems like mine, in contrast, are often treated using patience, which can be a hard medicine to take. I know it has been for me, but I finally improved and got back to concertina. How I was holding my concertina, and how I fixed it.