Sligjt pain under the skin of the abdomen while. Doing streching exercises...What is this? Am.I in. Danger?

Doubt it. Have you had any recent surgery involving the area? Do you notice any overlying skin changes? Can you recall straining any muscle in that area? Do you feel or see any mass? If no to all of these answers and pain does not persist or worsen then likely not a problem. If yes to any answer or symptoms worsen see your primary care doctor.