If you have chronic heartburn / acid reflux, you may have a hard time pinpointing exactly what it is you're eating that gives you trouble. I know I could never point to one particular food (it turned out I'm allergic to all dairy and all gluten, so pretty much everything I was eating every day!). When that happens, it may be something ubiquitous that's causing your trouble. Gluten is a protein found in wheat, rye, and barley. Because regular white flour is made from wheat, that means it's in almost everything (even sauces and condiments frequently use flour for a thickener). This is why I always suggest people head to an allergist for food allergy testing if they are having chronic heartburn (do this before you go to some mainstream doctor who will just tell you to take Prilosec without trying to get to the root of the problem). However, if you don't have money to spend on a doctor right now, you could try a gluten free diet for a while and see if that helps. Here are some sites that can help you get started:
http://www.gicare.com/pated/edtgs06.htm -- gives you the basics on what a gluten-free diet is and also helps you decode ingredient lists that can contain hidden gluten.
http://www.glutenfreeforum.com/ -- a very active form that's full of people on gluten free diets, who can give advice