Hi, I'm 19 And For Years I Have Had A

Hi, I'm 19 and for years I have had a hard movable lump inside my right labia majora. I have never thought of it. It doesn't hurt, has never changed size, isn't detactable until you feel the skin and has never hindered any movement. As I have gotten older though I have realized this was not normal and wanted to know what it could possibly be.