I am a 34 year old female, I have a small hard lump in my lower left abdomen, I have been experiencing pain on and off for aprox. 1 year. This past week, I have also been experiencing severe lower back pain with the abdominal pain. My medical history includes 2 c-sections, and a tubal ligation. I have had gallbladder attack previous, and last year when I compained to dr. about my abdomen he believed it was endometriosis. Any ideas what this could be?