Painful periods

I have had painful periods from the first period, but for the last 2 months it's been even worse. Sometimes the pain lasts for 2 weeks, going away during the day, but then coming back at night. There is little to no bleeding as well. I have the mirena iud. I have been seen at the E.R and my gynecologist but they can never find anything like cysts, implanted iud, or even signs of a miscarriage. Has anyone else gone through this??? If so, what did you do? I'm at my wits end and so is my poor husband. Help!