Hi. Hiatus hernia
can produce similar symptoms that are observed in angina
of cardiac origin. But if you have been screened with an ECG during the episode of pain or immediately thereafter and its normal, then I think a cardiac enzyme screen would be helpful as this should not be elevated in hiatus hernia. Moreover and ECHO would help to assess your cardiac function, ejection fraction
and to look for any regional wall motion abnormalities. With these tests you can further confirm whether there is some cardiac disease or not. Once all this is negative, you can definitely be sure that the pain was due to hiatus hernia and reflux. Moreover you are very young for cardiac disease, though this cannot absolutely rule it out at this age. Thank you.