Hi! There are various causes for left lower abdominal pain. I understand your wife has undergone several investigations. Please go through this and see if something was missed. Pain and discomfort on the lower left side of abdomen just below and to the left of navel can be due to several causes such as Crohn’s disease 9this is difficult to diagnose so check this out), diverticulitis, infection in kidney, kidney stones, adhesions (if she had prevous abdominal or pelvic surgery), polycystic ovary, IBS, constipation, and an abscess in rectus abdominis muscle or psoas muscle. Take care!