Doctor i have a concern my boyfriend and i had unprotected sec and he came inside me 4 times i started birth control a day after could i get pregnant

Yes you could : If you are healthy and have unprotected sex with a fertile man about the time of your cycle when you ovulate, your risks of getting pregnant increase greatly.. Starting your oral contraceptive pills a "day after" is very unlikely to prevent you from getting pregnant. Be safe. Ask a knowledgeable Gyn for a Long-Acting-Reversible-Contraceptive like an IUD or a subdermal implant and use condoms too.