Perineal pain after sex may be caused by sexual stimulation, transgenital retrograde infection, malignant tumors of the reproductive system, urinary tract stones and other reasons. 1. Sexual life stimulation: excessive movement during sexual life, strange posture, thick male penis and other factors lead to penis, vagina pressure, perineum area violent impact and the above symptoms. 2. Transgenital retrograde infection: before sex, both men and women do not clean the genitals, perineum and other parts of the body, and the environment of the sex life is dirty, leading to transgenital retrograde infection, pelvic inflammatory disease in women, and urethritis and other diseases in men, which will lead to the symptoms mentioned above. 3. Malignant tumor of reproductive system: female cervical cancer, male prostate cancer and other malignant tumors cause perineal pain due to contact stimulation during sexual life, resulting in rupture of tumor tissues and bleeding. 4. Urinary stones: when stones appear in urethra, bladder and other parts of male patients, sexual life may aggravate the friction between stones and mucous membrane due to change of position, local impulse stimulation and so on, so perineal pain is caused. Perineal pain after sex may also be caused by other factors, it is recommended that patients go to the regular hospital in time for treatment.