Thanks for posting your query.
Do you have undergone ECG, 2 D echo and coronary angiography?
If all investigations were normal, then have you gone for electro-physiological study of heart and holter monitoring ?
What was their reports?
Yes.. burping may be related with gastric problems and you should go for endoscopy.
You may have gastritis and in severe form peptic ulcer disease
Have you gone for thyroid profile and serum electrolytes level? what was their reports?
Other possibilities may be hyperthyroidism, pheochromocytoma
, mitral valve prolapse
, panic attacks.
If all relevant investigations are normal, then you should go for psychiatrist
Get well soon,
Dr. Mayank Bhargava