invisiblepain2, my little understanding of CAPS is that it is an autonomic disorder. As such it could be treated by an injection called a stellate ganglion block, which is said to reset the autonomic nervous system. I think it more likely to be the incarcerated umbilical hernia. Trapped hernias don't have blood supply and that eventually causes cell death. If yours is incarcerated you need surgery whether it is the cause of pain or not the cause of pain. I'm afraid that the increasing pain is a warning. Hernia surgeries are so common that surgeons become quite adept at removing them. Some 65% of cases of umbilical hernias eventually need surgery.
I've no medical background and am not in a position to outguess your physicians, but I'm with the surgeon.