Hello. I'm 16 Years Old. I Have Never Had Sexual

Hello. I'm 16 years old. I have never had sexual intercourse. I'm feeling pain on the left side of my vagina. It's on the outside of my vagina and it concerns me. It seems to be swelling. I've googled my symptoms and everything I've read says that it has to be an STD, but that's impossible. There are no bumbs or redness, and I've never done anything. What could it be?