I Suffer From GERD And Have Tried PPI And Acid

I suffer from GERD and have tried PPI and acid reducers and seems to be in check, however whenever I exercise, I.e. Swim or bicycle I experience an upper chest discomfort like esophageal burning but after finishing half of my routine the next part seems free of the symptoms. Other than going to a Dr. How can you distinguish between GERD and angina from the heart?
YYYY@YYYY