I want to be on birth control (im 16)

I want to be on birth control, not because I'm having sex (I'm not) but my periods are so bad. my cramps put me at the point where everything hurts and I can't even get up to pee. sometimes it's heavy, sometimes it's not but the symptoms are always the same. my parents know I have a hard time with them but they won't put me on the pill because they think im going to go around with my boyfriend to have sex. is there any idea of how I can convince them to let me🤦🏾‍♀️ I just want to ease the pain of my period