Hi there. You need not be worried. You are too young for things like Stroke, Heart attack etc. It's rare at your age. How ever the symptoms you mentioned are vaguely indicating towards angina but then again its rare at this age. You are most probably anxious and worrying too much. For your satisfaction you can always get an echo cardio graphy done which will put aside all doubts. Your symptoms are most likely weight related. Have some regular basis exercise. Drink lots of fluids. If it pains real bad you can use crocin (acetamenofen) for relief.
Excessive acid reflux can also be one of the cause for this kind of symptoms. Other than using antacids and ppi's best way is to eat light, have multiple but less meals and always exercise (walking, running etc)
Next Steps
repeat echocardiography and do exercise