Endometriosis occurs when tissue similar to the uterine lining grows outside the uterus, causing symptoms such as pelvic pain, painful periods, and infertility. Though the exact cause is unknown, factors like retrograde menstruation and immune system issues are believed to play a role. Treatment options include pain relief, hormonal therapies, and surgical removal of the tissue. Managing endometriosis often requires a blend of medical treatments and lifestyle changes to reduce symptoms and enhance quality of life.