A painful bump on the wrist can be caused by boils, tendon sheath cysts, and osteophytes. 1. Boil: a purulent infection of the soft tissues around the hair follicle, which causes redness and swelling of the skin in the early stages of the disease, leading to hard knots under the skin, which may lead to the symptom of a hard lump on the wrist. 2. tendon sheath cysts: a cystic swelling that occurs in the tendon sheath of the joints, and the local long-term posture of over-exertion, local friction, etc., which may lead to a hard lump on the wrist pain. 3. Osteomalacia: most of the factors related to age, calcium loss and heavy physical labor, belonging to the degenerative lesions of the bones, the local osteophytes can also lead to wrist bumps and pain. There may be other reasons for the bump on the wrist pain, and you need to go to the hospital in time to check and clarify the cause.