I have sharp aching grabbing paun in my left upper quadrant what can this be?

Not usually serious. If "paun" is "pain" then the answer is a host of things, which can range from simple things such as a strained muscle or a rib fracture on the left lower chest wall, to more serious disorders like peptic ulcer disease or diverticulitis. I have recently even seen one such patient near your age with a splenic problem. If it persists see your doctor or surgeon.