If you eat at about an hour or two hours before you run...The sharp pain in your abdominal area that you felt is maybe the cause of the acid...Because at that time, the food that are present in your stomach are still digesting..And isn't that when food is digested in the stomach, acid is present?
According to David Ng, PhD Student, School of Pharmacy and Medical Sciences.Food travels down the esophagus at a rate of approximately 3 to 4 centimeters per second (1 to 2 inches), and the entire process takes about 5 to 6 seconds. In the stomach, food tends to hang around for a little longer and this depends on a variety of factors including the amount of food you have consumed, how much fat it contains, and also the acidity of the stomach. However, all food should have left the stomach within 2 to 4 hours.
So at the time that you run...maybe the acid had flown back...That's the reason why you felt pain in your abdomen.
But always remember to consult a doctor if ever the pain worsen.