What Causes A Large Lump On The Vaginal Opening?

I have a large soft lump at the entrance of my vagina. I have had three children (two with episiotomy, the last with natural tears). I also had a full hysterectomy, cervix out as well five years ago. The lump feels like the wall between the rectum and vagina has prolapsed toward the vaginal opening. It does not hurt and doesn t cause any issue during intercourse. On occasion it feels like when I am constipated a bit that some of the bowel movement gets stuck in that spot. Is this a common issue for women who have gone through the procedure and vaginal births that I have? I am also overweight by quite a bit, if that makes a difference. Something I am currently working on.