Hello, As you are on birth control pills, you probably experienced breakthrough bleeding at some point, which also often shows as a brown discharge. This was happened as your body adjusts to the artificial hormones in the pills, which work like natural hormones to regulate your uterus when it sheds its lining. This could also possible in anovulatory cycle. This is when you bleed during your menstrual cycle, but do not release an egg or ovulate. If you don t ovulate, your body never senses the need to shed the lining and you may not have a regular period. There are many causes for painful sexual intercourse ranging from emotional distress, lack of lubrication, endometriosis etc. Thus a through pelvic examination and other investigations like ultrasound abdomen is need to identify the cause. Please consult a Gynecologist and investigate for the cause of painful sexual intercourse. Hope this helps. Wishing you good health.