Worried about side effects

Hi everyone, just searching for some friendly advice on birth control. I started getting my period in 6th grade when I was around 13. At 16 my period cramps started to get so bad that I would have to stay home from school when my period came around, and no pain meds would take the pain away. When I was 17 my doctors prescribed with Naproxen because that drug is supposed to ease extreme menstrual cramps. After taking it for a short period of time I noticed really concerning side effects. I noticed that I would have sharp aches and pains shooting up my left leg and left arm, my heart rate always sped up significantly, and I would get headaches. I stopped taking them after that and the doctor referred me to a gynecologist and also recommended that I get on birth control. I'm 18 now and a lot of the girls I know that have gone on a form of birth control gained a lot of weight, and that's a concern of mine. I don't think that's a concern for most women but I'd like to hear how it worked for other women so I can get a better perspective.