The primary symptom of endometriosis is pelvic pain, often associated with menstrual periods. Although many experience cramping during their menstrual periods, those with endometriosis typically describe menstrual pain that's far worse than usual. Pain also may increase over time. Common signs and symptoms of endometriosis include: 
Painful periods (dysmenorrhea). Pelvic pain and cramping may begin before and extend several days into a menstrual period. You may also have lower back and abdominal pain.
Pain with intercourse. Pain during or after sex is common with endometriosis.
Pain with bowel movements or urination. You're most likely to experience these symptoms during a menstrual period.
Excessive bleeding. You may experience occasional heavy menstrual periods or bleeding between periods (intermenstrual bleeding).
Infertility. Sometimes, endometriosis is first diagnosed in those seeking treatment for infertility.
Other signs and symptoms. You may experience fatigue, diarrhea, constipation, bloating or nausea, especially during menstrual periods.
 The severity of your pain may not be a reliable indicator of the extent of your condition. You could have mild endometriosis with severe pain, or you could have advanced endometriosis with little or no pain. Endometriosis is sometimes mistaken for other conditions that can cause pelvic pain, such as pelvic inflammatory disease (PID) or ovarian cysts. It may be confused with irritable bowel syndrome (IBS), a condition that causes bouts of diarrhea, constipation and abdominal cramping. IBS can accompany endometriosis, which can complicate the diagnosis.