Maybe be gastritis or muscular origin...repeat ECG now if no issues then try eating several small meals instead of three large ones whenever you can...Avoid foods that irritate your stomach, especially those that are spicy, acidic, fried or fatty... avoid coffee,tea etc... Stress may make your gastritis symptoms worse...Stress may be hard to avoid, but you can learn to cope with it. If you have trouble relaxing, consider calming activities, such as meditation, yoga etc...sleep with head raised position and have dinner at least 2 hours before sleep..take over the counter medications with above..consulting doctor if symptoms persists.