I had abdominal surgery 3 months ago and I have a 5 inch vertical incision that runs through my belly button. Is it a myth that you cannot get back abdominal strength after being cut vertically because of the muscles that are cut? I can barely do any type of ab exercises now and if I do, I hurt in the abdominal area for days. It seems like a lost cause, but I hate losing all of my core strength. What type of exercises are good for this problem?

I am absolutely sure that is a myth, for two reasons. One is the surgeon doesn't cut through the muscles most of the time, they are split and pulled aside. Further, people recover from having muscles cut in two all the time, as long as they are neatly sewn back together.

It may be that you've just lost a lot of strength, and need to build back up slowly. It also may be that some scarring from the surgery is causing you pain. You may want to consult with the surgeon or your family doctor about how best to recover your abdominal strength.