Please keep in mind you need to see a gynecologist if you are sexually active, especially since this could be an std. A dr can't tell your parents what is going on without your permission. Have a friend take you to a clinic at the very least, you are young and don't want to risk your future fertility by avoiding treatment. Take care of yourself.
Hello!!
Sounds like you need to take a trip to the good ole doc. You are 16 and sexually active.. I am NOT judging you at all. I, as a parent of a girl and yes she is only 15 months old, lol... however, I think its important to tell your folks... I know you're scared, but think of how they'd feel if something was truly wrong and they didn't know.. I hope when my DD is your age that she will be able to talk to me about anything. I truly hope all is well!! And I am not preaching, lol.
Unfortunately no one here can diagnose you, you need to see a medical doctor to get to the heart of the matter. Pain should not be ignored and the longer you let it go the more damage you could be putting yourself in. If this persist please don't let it go, just go and see your doctor. Take care, I hope you feel better soon.