ovulation pain

I have severe excruciating ovulation pain. I almost die with it. Have tried different painkillers but have not succeeded with any. I was on birth control pills for year and a half and my body got adapted to it. Tried muscle relaxants yesterday which kinda made little less but still when it pains, I have to sit down holding my stomach. What works for you guys? Also what is the diagnostic procedure to confirm endometriosis?