Chronic pelvic pain associated with endometriosis is poorly understood. This study is an effort to better understand pelvic pain and identify novel medical approaches for understanding it and treating it. We will examine the relations among sex hormones, pain processing, immune system substances and pain related genes. We will also examine changes in levels of hormonal and immune substances in the blood, endometriosis lesions and normal endometrial tissue. Myofascial pain has been noted in women with endometriosis and chronic pelvic pain. We will study how the nerve, muscle and skeletal systems are involved in pelvic pain by performing an in depth pain assessment. Finally, stress plays an important role generating and perpetuating chronic pain. We will examine how the hormones related to the stress response may be altered in pelvic pain. Comorbidities of endometriosis including autoimmune and other disease states. We analyzed a survey of almost 4000 women with surgically diagnosed endometriosis conducted by the Endometriosis Association. Almost all responders had pain (99%), and many reported infertility (41%). In this cohort of women with endometriosis, hypothyroidism, fibromyalgia, chronic fatigue syndrome, autoimmune diseases, allergies, and asthma are all significantly more common than in women in the general U.S. population. In the next two years, we are going to analyze the remainder of the survey to examine the types of medical and surgical treatments these women have experienced and their effectiveness, as well as other co-morbidities.