Penile swelling and pain after erection may be caused by short tethered cord, acute injury, prostatitis and other factors. 1. Short tethered ligament: Men who have a short tethered ligament and are circumcised may experience pain and swelling after erection, which may also affect their normal sex life. 2. Acute injury: when the penile area suffers an acute injury, the penis may cause excessive tension on the damaged area after erection, which may easily cause symptoms of penile distension and pain, and in serious cases, it may also lead to localized rupture and bleeding. 3. Prostatitis: it may be related to unclean sex, poor hygiene and other factors, which can lead to enlargement of the prostate gland, repeated congestion of the prostate gland after erection may cause pelvic area distension and pain, such as perineum, scrotum, penis and other parts of the body, accompanied by urinary incontinence, dribbling of urine, frequent urination, urinary urgency and other symptoms. The swelling and pain after erection can also be seen in other causes, it is recommended that patients go to the regular hospital in time, identify the causes, standardized treatment under the guidance of the doctor, and strive for early recovery.