Dear Doctor
Normal exercise ECG and Echo practically rule out a heart problem
Relief by these medicines suggest stomach and/or food pipe problem. An
endoscopy negative once does not rule out... Absence of proof is no proof of absence...
I strongly suggest to have the upper GI endoscopy REPEATED - may be at at a different centre > oesophagitis could have been been missed or cleared first time; Reflux is not obvious every time and so on
Good Luck