Hello~I am thinking it could be an ovarian cyst, they present with the same symptoms that you have described. The pain in the lower back and side is what gave me the clue. If possible, ask for a pelvic ultra-sound, it will certainly show any fibroids or cysts that you may have, the doctor will be able to help you accordingly if this is indeed the reason you are having the pain.
As to the lump, that could be scar tissue from the surgeries.
I have put in a request for this to be moved to the women's' health forum, there will be ladies that will be able to help you with more info.