Felt nauseous and short of breath during exercise. diagnosed with gerd after normal chest x ray, ecg echo stress test. panic attack gerd or heart?

Most commonly GERD: with normal CXR,ECG and echo, findings are less likely cardiac. Exercise has been known to trigger reflux. Figure out if its your routine (crunches on a full stomach), or diet (aggravating foods, coffee, OJ). Try some PeptoBismol before exercise to see if chnages. Keep a diary of when it happens, how you feel, and what you had to eat that morning. It will give you and your doc the best picture.