What Causes Chest Pain After Eating Inspite Of Taking Protonix?

My father is 81 years old reports after breakfast chest pain and heartrate 170 beats per minute. He is black male diabetic hypertension and high cholesterol. He went to the Va hospital 2 weeks ago with similiar symptoms they did Ekg and stress test and did not detect anything felt this may be associated with gi so gave him Protonix before meals. These symptoms are reappearing as of this morning. I am concerned?