No, I don't think a nodule always means RA. My Mom doesn't have RA, but she has spent a lifetime as a very active seamstress, which means a lot of repetitive motion in her fingers, wrists, elbows, shoulders, etc. She also developed nodules.
Do you know if it's a nodule on the bone (aka a bone spur) or a nodule in the tendon or soft tissue? If it's a bone spur, surgery can help. If it's soft tissue, an injection of steroid along with daily massage, could help dissolve it.