Hi, many thanks for the query!
Well, a black shadow there indicates nothing but air/gas i.e. your colon
is loaded with faeces.
You haven't mentioned exactly what digestive problem you are having, whether the stools are hard...
You need to do- USG (Abdo-Pelvis), CBC, Hydrogen Breath Test
Eat high fibre diet, avoid milk & milk products if lactose intolerance
is diagnosed, drink plenty of water, do regular exercise.
Take stool softners if hard stools, pre- & pro-biotics, antacids with your doctor's opinion.
Wish you a good health.