What Causes Periodic Pain In Chest Along With Stinging In Sternum?

I m a runner and have been experiencing Chest pain periodically. I ran 20 miles yesterday and didn t each as much as I should have and had a beer yesterday and today started feeling a scary stinging pain on the sternum area but I think it s because I was hungry. I ate and now it feels better but I am worried as ive head low cholesterol in the past-I don t want to have a heart attack. I ve also had a few acid reflux cases this week. I have always ate a ton of breads and carbs but I m wondering if that can contribute to feelings of acid reflux.