My girlfriend and I had sex, am 21 and she is 22 and we used condom. We earlier also had sex but this time I don't know something has happened to her, after a hour of intercourse she started going to bath room and start complaining about her urination she says her lower stomach hurts and its like the urine has jammed inside. And it has been two weeks and its frequently happening to her. She is far nowadays and she is shying to go to doctor alone. And we had eaten much oily chicken that day actually Indian roast and she ate 2 leg pieces is it becoz of that oil.. please help me..

She needs to see a doctor. We can't diagnose this online.

At her age, she needs to see doctor on regular basis, there is not reason to be shy.
So have her take a friend, or mom or someone with her

It's dangerous to have urine back up in the bladder and kidneys.
She could have an infection, either bacterial or yeast or both. They can move in to small cuts of delicate tissues around the vagina, and it's common with sexual activity, especially when a woman is just starting to have sex.
It is EASY to treat if treated ASAP!! The doctor might just prescribe something without examining her, or ask for a urine sample. So go!