I am 29 years old. After hard sex i have problem in penis. I have these symptoms is mine. Infection of the bladder tube (urethritis) causes pain while passing urine, and there may be fluid (a discharge) dripping from the opening at the tip of the penis. Urethritis is often due to a sexually transmitted infection (venereal disease). It may lead to pus formation (an abscess) in the shaft of the penis, which causes severe pain and swelling.