It sounds like this is a very uncomfortable situation for you. The best thing for you to do is to see your doctor
right away so that he or she can evaluate the area and identify what is causing your symptoms. From what you describe it sounds as though you may have a small abscess
or infection in the genital skin area. This can happen anywhere on the body and has nothing to do with whether or not you are (or have been) sexually active. If this is an abscess (or pocket of infection), your doctor will likely want to drain it, as well as possibly treat with antibiotics. If you don't feel comfortable seeing your pediatrician
about this, you can always see a gynecologist who will also be able to take care of this for you. Hopefully this is something that will only happen once, but in some cases people can get a very aggressive bacterial that colonizes their skin and can cause subsequent abscesses or infections around hair follicles in susceptible parts of the body. It is important that you see a physician for evaluation and treatment now.