You need surgery,but. Our research that will be published soon shows two very accurate predictions of endometriosis. First, if you had bad periods (worse than peers or missed school )as a teenager, you have nearly 100% chance of endo at surgery. Second, testing for ovarian reserve with Clomid (clomiphene) challenge test: if abnormal 90% chance of endometriosis at surgery. Need good excisional surgery not band aid.
Ultimately at hospit. Endometriosis can be definitively diagnosed at the time of surgery. There are certain symptoms or diagnostic tests that are suggestive for endometriosis, but are not definitive. Therefore the answer is at the hospital.