Hello dear
Warm  welcome to Healthcaremagic.com
I have evaluated your query in details  .
*  This is in relation with different  possible  causes as
    -  
gastritis  or  
duodenitis  -  ulcer  stomach or 
duodenum  -  digestive
    enzyme  disturbances  -  liver  disorders  -  biliary  tract  issues  
    -  pancreatic  pathologies  -  certain food  related  -  other  systemic
    disorders  affecting  gastrointestinal  tract  .
*  Guidelines  for  better  recovery
Prefer soft , light , bland , vegan diet till possible .
Consume more of whole grains , cereals , pulses , legumes , organic fresh fruits .
Avoid  all oily , spicy , non veg , hot beverages , junk foods , hot beverages 
Avoid over eating , prolong fasting .
Avoid resting upto 2 hours after meals .
Fix your timing of breakfast , lunch , dinner  till possible .
Avoid late night parties , dinners .
Keep the head end of the bed elevated for 30 degrees  when  resting .
Have  regular walking in fresh air , exercises , YOGA .
Avoid smoking , alcohol if consuming .
Avoid stress , 
anxiety .
Maintain to have regular sound sleep of 8 hours .
Intake  of  
Proton pump inhibitors as 
omeprazole or 
pantoprazole on empty
stomach  1 hour prior to lunch  ;  antacid  syrups  as  mylanta or others according  to the  advise of your doctor  helps .
Hope this  will help  to clear your doubt   .
Wishing you fine recovery .
Always welcome for any further assistance anytime .
Regards  .