Suggest Treatment For Sharp Pain In Lower Left Abdomen

Iv been geting stomache pain since last year it goes sometimes for couple days then paradine fort dsnt help sometimes it comes sharp in my left lower stomache like quick knifes sharp in ultrasound thay found nothing sometimes the pains also flick in the top ov my legs that it stops me in my tracks iv had low iron for years had to have iron transfusion few times I m worried it s serious and thay not picking it up