Hi,
Welcome to health care magic,
It is likely to be gastritis but the chances of having gastric ulcer should also be ruled out by endoscopy although ealierly it was not suggestive of ulcer in 2013.
Causes of gastritis are helicobactor pylori infection,oily and spicy diet,or drug induced.
You can go for routine blood count,ESR,
urinalysis with ultrasound abdomen with upper GI endoscopy to rule out other gastric pathology and to confirm
gastric inflammation.
You may require h2 blockers like ranitidine or
proton pump inhibitors likepantoprazole,
rabeprazole etc with cytoprotective drugs like sucralfate,
misoprostol etc.
It underlying cause is H pylori then you will require triple drug regimen means two antibiotics and PPI.
Consult your gastroenterologist who can order the tests and can prescribe you proper treatment.
Regards,