question: I have a slight lump on the top of my hand in the area of the adductor Pollicis Brevis Muscle. It is slightly painful (not too bad though). FYI I play a lot of tennis and am a personal trainer so I use my hands a lot. Could it be arthritis ? (I do not think it is ganglion since I do not believe it is next to a joint or tendon.) Should I get it looked at ? What could it be?