When you have sour smelling poop it could be caused by something you ate or you could have Malabsorption.
The Malabsorption is a common cause of sour smelling poop so you should see a doctor about the sour smelling poop to get tested for any health conditions.
Malabsorption is when your body is unable to absorb the proper amount of nutrients from the food you eat.
Malabsorption generally occurs when there's an infection or disease that prevents your intestines from absorbing nutrients from your food.
Another cause of sour smelling poop is Irritable bowel syndrome or Inflammatory bowel disease.
So if the sour smelling poop continues you should see a doctor because sour smelling poop is not usually normal in healthy people.