Birth Control????
Birth control is actually a decent way to reduce period pain and other issues.

HOLD UP I HEAR YOUR PROTESTS--

You do NOT have to be sexually active to take it! Plenty of people who aren't active like that take it just to reduce period symptoms. It's a fairly low dose too, and taking birth control for 5+ years actually reduces the risks of certain cancers!

If you're a certain age you can get birth control pills for free/cheap, though with the current political climate in the USA, Americans might be outta luck soon.

The only possible issues are A) You might have to buy the pills, and B) If you can't swallow pills you may have to find a workaround.