It's true nsaids can give you ulcers in the stomach lining. I had the same problem with cramping and downed a ton of nsaids. Soon I had pain all the time so I started taking dgl licorice as an ulcer cure and it worked beautifully! Although i never had medical evidence of an ulcer, it seems obvious now due to the circumstances. I hope it will help you; I'd take it occasionally if I were you to ward off ulcers due to the nsaids if you don't already have one.
I don't get periods anymore, but I have a theory about uterine cramping I ALMOST wish I could test out myself...I've recently discovered hyaluronic acid which has helped me with a myriad of problems. One of the things I apparently have is "connective tissue" weakness and the uterus is full of connective tissue. Now I'm wondering if it would have helped my cramps. If you want to try it, I buy it from vitaminshoppe.com where they call it "injuv", probably because hyaluronic acid is believed to be the substance scientists believe is responsible for extremely long, healthy lives of a small group of people on an island featured on 20/20. I know I would have tried anything to end the cramps...hope this works for you.