Okay, this is really embarrassing... but here goes nothing. 
I'm a 16 year old female, and have been masterbating for 2-3 years now. Recently I discovered a lump right under my vagina, above my anus. I'm really worried as to what it is. Is this related to masterbation? I'm a virgin, so it can't be anything dealing with STDs. I need help, please. Thank you.