You may not get a flat belly even with muscle tightening if you have too much intra-abdominal fat. A photo is insufficient to determine this, and you'll need an ABPS certified/ASAPS member surgeon to examine you. Regardless, why would anyone go through an abdominoplasty and omit what is likely going to improve your result, just because of the fear of additional pain? It doesn't make sense, especially given the long acting local anesthetics available that diminish that pain substantially. Best of luck!