this nodule sounds like it is in a tendon. Nodules in tendons in the palm of the hand can be quite uncomfortable and most often represent true benign nodules or scarring/fibrosis in the tendon. Sometimes thickening in the tendon can cause the finger to get stuck in a flexed position and you have to pry it open; we call this a trigger finger. If it continues to bother you, the best thing to do would be to see an orthopedist who specializes in hands for consideration of a steroid injection into the tendon. Also, a splint to keep the finger open and stretched might be useful.