Help!

So I need help choosing what birth control would be best with my situation. The second I start, my cramps and back pain are seriously the worst. A while ago I had broken my back and it healed weird so of course that doesn’t help and I’m not one to cry from pain but the cramps and back pains I get are to the point I can’t move. I once stayed at my boyfriends house and it had started just before I had to leave to go to work and it was so bad I couldn’t drive. So what I’m really asking is what would be best to just help with the pain of the cramps? I’ve heard the IUD has a 50/50 chance of that happening but I really haven’t heard/researched much about it because I don’t know what to really search for. If someone could help that would be awesome.