Why does my stomach hurt after eating something then walking?

You may be swallowing larger chunks of food if you eat while walking. It would be good idea to sit down and eat slowly by properly chewing your food and savoring it. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs.