What Causes Burning Sensation In Lower Abdomen?

Hi doc.last year i had burning sensation on my lower abdomen,i cudnt tel its cumng from my overies or fallopian tubes.i went to c a doc bt dd nt find anythng infected.also went to gynae and also nothng.Dd da pap smear and nothng ws wrong.abdominal sonar.dd ol dose in same year stil da sensation ws procedin.gave me many antiboitics,injections&stil burning.what is realy wrong?