Hello
I share your concern.
Looking at your description it might be related to
acid reflux or GERD due to loss of tone of lower oesophageal sphincter or stomach
hyperacidity.
I would advise you to follow these guidelines for a while.
1. Avoid fatty fried and junk food
2. you should take small and frequent meals, avoid overeating
3. have lots of fresh fruits and boiled vegetables or easily digestible food.
4. avoid carbonated or caffeinated beverages
5. Don't lie down immediately after having food.
6. use pillow while sleeping.
7. you should take antiacidity medicines like
pantoprazole or
ranitidine group of drugs with antacids if symptoms aggravates all of sudden.
8. reduce body weight if you are obese or overweight
9. no smoking or alcohol consumption.
Since you have already evaluated by an endoscopy, so you need to take all these measures because you are having
gastritis, and all the life style modifications will add in to healing.
Hope this answers your question, please feel free to ask for follow up question, I will be happy to help you.
Best wishes