Hi. sometimes when im at the gym doing strenuous weight
ive had ekg recently and it was fine and have had tests previously like and echo whixh showed no defects.
I would explain as follows:
Welcome to Ask a Doctor service!
I passed carefully through your question and would explain that your symptoms could be related to gastro-esophageal reflux.
I don't think that your symptoms are typical of a heart disorder, as burping is really atypical of any cardiac disorders.
I don't think that it is vagal nerve too, as you experience tachycardia, which is the opposite of vagal nerve response.
Anyway, an exercise cardiac stress test would help definitely exclude any possible cardiac issues.
Hope you will find this answer helpful!
I remain at your disposal for any further questions whenever you need!
Dr. Ilir Sharka, Cardiologist