Thank you for the query.
Your symptoms are most likely caused by acid reflux
disease or peptic ulcers. Pain in the upper middle abdomen, nausea after a meal are quite characteristic for this condition. However, always when the chest pain
appears, heart condition should be verified.
I suggest you to have heart ECG performed as well as stress test
. Upper GI endoscopy with Helicobacter pylori
test should be also performed. Abdominal ultrasound seems advisable to rule out other possible reasons of your symptoms (like gallstones)
Hope this will help.