sharp pain in groin under ostomy

If it's not constant pain, but rather hurts when you turn or move, it can be a trapped nerve from the surgery. I had that after a low abdominal surgery.
That kind of pain usually goes away by itself after days or weeks, but it can be diagnosed and treated by an injection of a local anesthetic (I don't remember exactly what) in the area that numbs the nerve.
My pain went away in a few days, so I never got the injection.