Yesterday I was having some really bad cramps, when I got home from work I felt like I had pulled a muscle in my pelvic area. When I woke up this morning to take my shower I was cleaning my vagina and a felt a lump the size of a cherry right at the entrance. I don't know what it could be. I have only had one partner for the past four years. It hurts to walk and I can't sit or bend without being in pain. What could it be?

It could be a number of things that range in complexity from something as simple as an ingrown hair to something more serious like a STD. To be sure you need to have it examined by your doctor.