How awful! I hope they figure this out soon.
Your dog's stomach flipping problem is called a GDV which stands for Gastric dilatation volvulous. It occurs in deep chested dogs who eat their dry food very quickly than drink a lot of water. The dry food soaks up the water like a giant food sponge thereby over filling the stomach. The stomach becomes so filled by food mixed with water and gas that it turns upside down on its axis. The stomach is just a balloon-like bag joined at both ends. The stomach is freely movable except for the two ends. One end is the esophagus, the other is the duodenum (beginning of the small intestines). Both of these ends contain blood vessel and nerves. When the stomach turns the ends become constricted, pinching off the blood vessels primarily. When the blood vessels are completely pinched off, as they were in your dog, the blood becomes stuck in organs, such as the spleen. With no outlet for the blood the spleen continues to fill with blood and becomes congested and enlarges. The spleen takes up quite a bit of space in the abdomen when it is congested and often has to be removed during the corrective procedure performed on your dog. Since your vet could not flip your dog's stomach back completely during the surgery, is he confident that it has returned back to normal on it's own at this time?
Your veterinarian may be talking about the scar tissue inside your dog's abdomen and not the surface scarring. I am sorry about all the extra vet bills but I believe you need to find out definatively what is causing the pain so that it can be reticified. Have you tried using the pain medicine and has it helped? Has an abdominal ultrasound or MRI been performed? Unfortunately, sometimes an exploratory surgery may have to be performed for diagnosis and treatment, unless you find that the pain medication is sufficient to help her with her bouts of pain.
Lastly, it may be possible that the pain is unrelated to her surgery and may be the result of spinal pain, or Lyme disease, for example. Perhaps, this too can be investigated if it has not been done already.
If you have any further questions please don't hesitate to ask! Please keep us updated!