What Does Slightly Painful Small Lump Between Vaginal Opening And Anus Suggest?

In the shower this morning I discovered a jelly bean sized lump in between my vaginal opening and my anus more so to my left side. It hurt when I put pressure on it and I can kind of feel it when sitting. The pain is not terrible more of just a "hey I'm here" kind of pain. It was not there yesterday it only just showed up either during the night or this morning before getting in the shower. I'm a 22 year old female, sexually active. I've had the same partner for over a year with no problems there. What could this lump be?