Pain with coughing is normal after a tummy tuck. Most surgeons use very strong sutures and multiple layers of repair to avoid loss. Typically you hear of feel sutures popping and you notice a new bulge that wasn't there before. If you did not experience that, then loss of the muscle repair is unlikely. Try not to worry and discuss this matter with your surgeon at your next visit. Best wishes on your recovery!
Relax. What you have experienced is not unusual. When the muscle stitches "pop" patients report actually hearing them. If this happens, it usually involves the stitches in the upper abdomen. Patients may notice a new found bulge in the upper abdomen. This may or may not represent the release of the muscle in the area. Sometimes, the patient may form a localized seroma ( collection of fluid) which may appear as a bulge in the upper abdomen.Only a physical exam by your surgeon will determine if the cough affected yo in a negative way. Good luck