I have a nickel size lump or cyst between my upper thigh and pelvic area.   It occurs every 3 to 4 months and is painful.   When this happens I also get sores on my labia which is extremly painful.   After about a week to 10 days it heals.   Any ideas as to what this could be?   I dont have any ingrown hairs in the area and it always occurs on my left side.