Cramping while on birth control pills?

if you have tender breasts and had sex unprotected you are most likely pregnant. Birth control is never 100 percent effective. even tho you are on it it cant keep you protected. I would get tested for an std because it could happen and a hint even tho you are on birthcontrol it will never be completly effectiveand never have sex unprotected ever because chances of pregnancy are high know matter your on birthcontrol or not