I was at the gym yesterday and attempted to do a plank exercise when it felt as though I was stabbed in my abdomen. I ended my training session and went home.The pain was there consistently all night, it hurt to move. Today it has continued as mostly an ache all day when I m not moving, but if I move, it s a sharp stabbing pain. I just ate lunch, but now I feel nauseous, have a headache and it hurts really bad to sneeze.