Why I Am Having Pain on the Left Side That Feels Like Something is Ripping when I Move Certain Ways?

Postoperative pain can be a challenge to pinpoint.  It would be helpful to know how far out from your surgery you are and to know for certain that it was a tummy tuck.  Sometimes a nerve can be irritated during the surgery and many of the nerves to the skin are cut during the surgery.  It is possible that one of these is the source of your irritation.  It could be one of a thousand other things, including those unrelated to your surgery.  The good news is that most of the time, sudden, specific and short lived irritations like you describe go away as healing progresses.  CT can be useful in ruling out many of the things that wouldn't be expected to go away, but that degree of investigation is fairly uncommon unless the symptoms are really hard to explain.