Ganglion Cyst...I agree. My friend had this, and got rid of it actually by smashing it very hard with a heavy book. I would not reccomend that course of action as it was EXTREMELY painful!
Hi! In all probability you have a ganglion (cyst) or a neurofibroma. Both can cause pain in the wrist joint. A ganglion is a sac-like swelling or cyst formed from lining of a joint or from a tendon. A neurofibroma is a collection of nerve and fibrous tissue. If they are causing pain and pressure symptoms they need to be removed. Please consult your PCP to start with and get a referral for a surgeon. Take care!
Infection, bruise, healing bone break, muscle strain, cyst.... It's odd that it's mirrored though. I'd guess one of your activities may have strained your hands in a relatively mirrored way (like holding ski poles in both hands for hours).
I would definitely have your PCP look at it. Are you running a fever? Is the skin hot to the touch? To be safe he or she will probabl put you on antibiotics. Acetiminophen or NSAIDs may help with the pain and inflammation for now, but please get it checked!
Good luck and keep us posted!