I have a sex question...what could be wrong?

Either she is not well lubricated or you are just too "big" for her.....It's like elastic and it widens with continues use. Keep trying or start penetrating her with your fingers (not so healthy so keep fingers clean and no sharp ended nails ) also if it is legal in your country, get her a "smaller" sex toy to use for the meantime, it helps to widen up.Once she opens up, she won't feel so much pain during and after sex.Anyway the pain is normal when very young.

Far from being totally aroused, women often suffer from a condition called vaginitis. It makes her vagina contracts involuntarily, creating spasmic movements that affects or impossibilite penetration. The best remedy is starting very very carefully as adding lube will not cure the condition. She needs to be completely relaxed and most important, she have to be completely aroused, take your time on her, give a lot of tongue and most of all, be comprehensive.

try different positions and try to eat her out first to get her juices flowing my friend cilla had this problem and it wasnt the guy size either she tried a big one and a small one its just the body refusing to enjoy it . have you ever gotten her really drunk b4 and tried it ? she may jsut need to relax and open up more.

Since I had the same problem with my guy I suggest you do either one of these. (1) Just have allot of sex all the time for she will eventually get adjusted to you penis size, give it about a week or two. The other thing you can do is invite a guy with a HUGE cock to have sex with her and stretch her out that much faster. So if you are average 6" and 2" thick than find a guy with a 10" and 3" penis oh and If you find him send him my way please!!!

how does it hurt? the lube is for wetness. it can't be that otherwise it would hurt when you first get it in, about 1/2 inch.
she might have a medical condition that will require you to be a little more creative in your positioning.
examples: tilted uterus, shortened cervix, or anything in the pelvic area.
i found out i had a tilted uterus, just like my mother and grandmother. sex hurt the first few years i did it. then, when i figured it out from the doc, i learned how to move my body about 1/2 inch and it was totally different.just by raising my butt, or tilting my hips a little.
try putting a pillow under her butt when you are on top, that might help.
a little

you edited your question while i was submitting mine-did she go to one doctor or a couple? and if so, did they do a sonogram? my doctors told me the same thing until i became pregnant. my sonogram for pregnancy is what informed us of the tilted uterus and my ob immediately asked me if sex was ever painful. btw-she needs to see an ob/gynecologist, not a family doctor.

She might be too nervous or not ready as the time. Foreplay is best before penetrating. Spend more time on it, use some toys and be more romantic then just rush in, it should helps :)

she needs to see a Dr.

she needs to be wetter