###Human: Why are there bleeding, pain, and discomfort during sex? ###Assistant: Hello. The most common cause of post-coital bleeding is either vaginal mucous frictional lesions, and the other is cervical erosions or cervicitis (lesions over the cervix which bleed due to frictional injury during intercourse). It is essential that you should get speculum examination, and pap smear done to check for cervicitis, and any vaginal mucous lesions if any. Please avoid intercourse. If diagnosed then this may require a course of antibiotics for the next 10 days as would be advised by a gynecologist after evaluation. Please consult your gynecologist.