I'm 18 years old, I've only been with one person.. Since losing my virginity I have never been able to go to second round of intercourse because the burning pain will start.. The first round is fine and no problems, I make sure to use lube all the time so that can't be the problem. I'm also on the birth control pill. The pain doesn't subside till I go to the bathroom.. And when I urinate it burns.. Its an uncomfortable situation and its been over a year now

Sounds like a chronic UTI. Urinary Tract Infection

When I was a teenager it was called Honeymoon cystitis and is common.

This is what I learned:
- you might need a med like bactrim from a doctor's prescription
- after you clear it up, always make sure to wipe front to back after urinating
- make sure that you have a lot of foreplay so that your body is ready, otherwise being too tight will hurt.