> someone who can help you "play through the pain" so you don't have to give up your livelihood.

Playing through the pain may end up being the cause of you having to give up your livelihood. If it really IS tendonitis you don't want anyone - doctor or not - to help you "play through the pain". Unless you're planning on a short career. Being a Gigging Pro does not mean you are magically exempt from the body's vulnerabilities.

Make sure the specialist is fully aware of RSI and its issues because they aren't always. Don't just listen to the person who tells you what you want to hear. There really may not be any other answer except resting the injured area (don't know what the procedure is for arthritis, but if the advice is to stop, I'd stop). Playing the gig at all costs is stupid if it's going to put paid to your performing life altogether.