At your age, most common cause of Abdominal pain with vomiting is usually Acidity.
Acidity is a lifestyle disease ie dietary related
For prevention & Treatment of Acidity
One should-
-Avoid oily, Spicy & sour food
-Avoid smoking, Alcohol, tobacco, tea, coffee, cola drinks
-Eating meals every 2-3hourly
-Never skipping meals
-Icecream & banana are good
Next Steps
stool routine examination & usg abdomen