Do I have a UTI?

sorry if this is random but i would like to know that if you have a UTI .. will it sting when you have sexual intercourse? i am a teenage girl and about a month ago my doctor told me i may have a bladder infection because there is high amounts of red&white blood cells in my urine but he was not completely sure, he said it could have been from having the stomach flu a week before or maybe because i was sick at the time. i was supposed to have another urine test but i never got it. will someone please tell me if i have a UTI? i dont have much symptoms except for pain while peeing but mostly only after i had intercourse and pain(stinging) during intercourse.. please help (: if you have more questions .. ask away