I'm having really bad pains in my stomach after having sex,

Hi -
my name is jessica.
last weekend i had sex with my boyfriend for the first time.
we are both 16 years old and we both were virgins.
i am 5'2 and i weigh 94 pounds... 3 days after we
had intercourse, i started getting pains in my
stomach, the left side of my stomch is swallon
and hurts really really bad. i'm getting bad headaches,
back pain, it burns when i pee.
we used a condom and didn't even
have sex for too long, it was like 20 mins.
i have NEVER had my period and i still haven't.
during sex, my boyfriend kind of was ruff.
he started really slow, and then got really fast..
it kind of started to hurt tords the end. but i didn't say
anything cause' he seemed to be enjoying it.

i've went to doctors after doctors and none of them
can tell me why i'm having such major pains in my stomach.

i'm really worried =[
i don't know what to do -
i just want the pain to stop.
my stomach has been hurting for 4 days now.