Brief Answer:
shortness of breath can be suggestive of problem with heart.

Detailed Answer:
Hello and Thanks for posting your query on this forum.

Have gone through your details and i appreciate your concern.
As per your query Shortness of breath(Dyspnoea) is not a classical symptom of GERD or reflux disorder.
Post randial Dyspnoea(After eating SOB) is highly suggestive of cardiac problem particularly congestive cardiac failure.

According to Newyork heart association congestive cardiac failure is classified as-

Stage 1-Cardiac disease, but no symptoms and no limitation in ordinary physical activity, e.g. no shortness of breath when walking, climbing stairs etc.
Stage 2-Mild symptoms (mild shortness of breath and/or angina) and slight limitation during ordinary activity.
Stage 3-Marked limitation in activity due to symptoms, even during less-than-ordinary activity, e.g. walking short distances (20–100 m).
Comfortable only at rest.
Stage4-Severe limitations. Experiences symptoms even while at rest. Mostly bed bound patients.

Post prandial dyspnoea can be suggestive of stage 2 congestive cardiac failure.

Advice
Go for stress thallium test as coronary artery disease is usually the most common cause of CHF and associated dyspnoea.
Some basic cardiology tests should be done initially like
Treadmill test and 2d echocardiogram to see if there is any problem associated with movement of heart and to find the ejection fraction of heart.
Lipid profile should be done.
A pulmonary function test to differenciate cardiac cause from pulmonary cause should also be done.

Take in person secondary opinion from cardiologist(Physical examination including auscultation).

For bloating after taking food start taking proton pump inhibitiors like Esomeprazole 40 mg twice daily.
A probiotic like VSL#3 should be consumed daily to assist in digestion.As overa;ll digestion will improve problem of bloating will improve.
For acid reflux get a prescription for domperidon 30 mg once daily.It is a prokinetic drug which will prevent acid reflux.

However initially would strongly suggest you to go for complete cardiac evaluation and follow up with reports.

Hope i answered your query well.
Follow up with reports.

Regards.

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