Well, without a clinical evaluation it would be difficult
to determine the cause of your symptoms. Possibilities that may need
to be considered include medication side effect, UGI inflammation, GI motility issues, heart related issues, neuro-muscular causes etc. Since cardiac and GI exams have been clear, I would suggest considering an evaluation by an internist to look into other possible causes. After a cause is identified it can be managed accordingly.
Hope this helps.
Take care!