 [ Symptoms ] what may be the cause of my left calf muscle to burn when i walk i do sit for hours at work i have had mri and the mri appeared normal [ Disease ] get your blood sugar checked i am a retired architect and started experienced burning and cramping in my lower legs while climbing ladders stairs and walking irregular job sites went to the m d thinking it was old disc injury re surfacing nope it was type 2 diabetes which had developed a blockage in an artery in my groin you are lucky it got both my legs when you walk your muscles are demanding more blood flow i e oxygen that they can not get so they burn and cramp after decades with diabetes i have found that long seated positions can exacerbate weakened or diseased vessels common to diabetes needless to say i spent many hours doing that at my desk or a drawing board good luck