last night when sitting up in bed i felt a muscle in my lower middle abdomen tear then a sudden sharp pain . now when i sit up in bed or sit up action i get a sharp jabbing pain. Pain immediately subsides when i stop using my abdomen muscles. The pain runs from lower middle up to the middle of my abdomen. Did i pull a muscle that could have been previously strained from exercise i.e. yoga/sit ups? Again, only hurts when i use it i.e. sitting up in bed.