Why does my stomach hurt after eating?

For a long time I have had problematic epigastric pain, especially after eating. There are days where it hardly hurts, but it happens that I can not function narmal because of the pain. It happens that even after eating two sandwiches for breakfast I have ailments, sometimes I wash in the esophagus, larynx. I even thought it was something related to lactowlza, but there are not always such symptoms after eating, for example, cheese, although after eating yellow cheese, even in a small amount, I have almost always pain