It's probably nothing, but I suggest over reacting to hand pain if you're a bassist. If you have a family doctor who you can go to and health insurance, sit down with him or her and say "this is a problem to me because I am a bassist and I want to do whatever we need to to make sure that it doesn't become a bigger problem and keep me from playing." If he or she doesn't know you well, make it clear to them that you are not there for pain medicine, because they might assume you are, but just make it clear to them that you are determined to get better, but need their help.
Ask them what diagnositics they feel are appropriate, should you see a specialist? Anti-inflamatories? Physical Therapy? What?
Stay active in your care and keep them working for you.
Maybe that leads you to a Chiropractor or a Surgeon or a Physical Therapist or who knows, but it's a good place to start. It's also good to have someone to go back to and say "That didn't work for me. What else can we try?"
A single joint pain, probably not too much to it, but get ahead of it before it gets worse.
Also, talk to your teaher. Bassist have to really watch any pain like this. They will be attentive and concerned.
Troy