I had DREADFUL period pains which is why I went onto The Pill as I didn't want children either. There was a drug the name escapes me which was taken 2 days prior to an expected bleed in order to relax the muscles which caused the pain, it was the only thing that worked for me.
Maybe have a chat with a Pharmacist in your area, they have private rooms in most Chemists - then let us know?