Thank you for your question. Masturbation should not cause pain and should be pleasurable. Sometimes if you use a very firm hand or masturbate too frequently in a day it can cause pain. If you have an infection this can also cause pain. It is important to get examined and treated if you have pain. If you delay correct treatment the infection can spread to the bladder and other sexual organs. If you have had unprotected intercourse you need full evaluation and treatment for sexually transmitted infections. Pl see a doctor specialising in Skin and DVD hope this helps