Reason For Abdominal Pain After Childbirth?

Hi two years ago I had my daughter the birth was normal except for a manual removal of the placenta, since having my daughter I have been getting server abdominal pains that comes and goes, at first the doctor told me it's because everything was settling back after the birth, but I kept having them, I did take co codamol for the pain which I think was making them worse, making the pain spread all over my tummy, I couldn't really pin point where they came from I have since stopped taking co codamol and just take paracetamol the pain still returns and lately I can locate the pain to my lower left abdomen, when I get the pain I have diarrhea and I urine frequently these symptoms are only when I have the pain as I'm typing this I don't feel pain and don't have the other symptoms but I know it will return, the pain seems to start off mild then goes to server before disappearing I have had a urine test and blood test twice and they have come back normal, my previous medical history is as follow 3 children 2004 having a c section with my middle child please can u help :( I do have a weak bladder from the 3 children so I'm not sure if it's a symptom on Monday I did wake to a one off lower abdomen pain which was server but went shortly after I emptied my bowels this don't happen often tho