Hello dear  Nalina , hi
Warm  welcome to Healthcaremagic.com
I have evaluated your query in details  .
*  This issue  has  multiple  causative  factors  as  possibilities  
    -  stomach  ulcer  -  gastritis  or  
duodenitis  -  duodenal  ulcer  -  gastric
    outlet  obstruction  -  
gall bladder  issues  of  stone  or  others  -  biliary
    tree abnormalities  -  liver  conditions  -  diaphragm  issues  -  GERD due
    to  hiatus  hernia  or  others  -  enzyme  level  disturbances  -  pancreatic
    pathologies  -  systemic  issues  as  diabetes  or  else  affecting  GI  tract
*  Perfect  management  depends upon  the  cause  , still general  
    guidelines  can  be  given  as  under 
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 , carbonated drinks .
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 .
Manage  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 .
Keep your  BP , blood sugar , 
cholesterol , body  weight  under  control .
Later on may need  
ultrasound  or  upper  GI  endoscopy according to the progress .
Wishing you fine recovery .
Feel free to ask any further  queries .
Regards  .