Endometriosis (en-doe-me-tree-O-sis) is an often painful disorder in which tissue similar to the tissue that normally lines the inside of your uterus — the endometrium — grows outside your uterus. Endometriosis most commonly involves your ovaries, fallopian tubes and the tissue lining your pelvis. Rarely, endometrial-like tissue may be found beyond the area where pelvic organs are located.

With endometriosis, the endometrial-like tissue acts as endometrial tissue would — it thickens, breaks down and bleeds with each menstrual cycle. But because this tissue has no way to exit your body, it becomes trapped. When endometriosis involves the ovaries, cysts called endometriomas may form. Surrounding tissue can become irritated, eventually developing scar tissue and adhesions — bands of fibrous tissue that can cause pelvic tissues and organs to stick to each other.

Endometriosis can cause pain — sometimes severe — especially during menstrual periods. Fertility problems also may develop. Fortunately, effective treatments are available.

Symptoms

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:

1 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.

2 Pain with intercourse. Pain during or after sex is common with endometriosis.

3 Pain with bowel movements or urination. You're most likely to experience these symptoms during a menstrual period.

4 Excessive bleeding. You may experience occasional heavy menstrual periods or bleeding between periods (intermenstrual bleeding).

5 Infertility. Sometimes, endometriosis is first diagnosed in those seeking treatment for infertility.

6 Other signs and symptoms. You may experience fatigue, diarrhea, constipation, bloating or nausea, especially during menstrual periods.

Read more - https://www.mayoclinic.org/diseases-conditions/endometriosis/symptoms-causes/syc-20354656#:~:text=Endometriosis%20is%20a%20condition%20in,including%20the%20bowel%20and%20bladder