HI, thanks for using healthcare magic
It may be best to consider imaging of the upper gastrointestinal tract to determine if there is any damage or ulceration of the
esophagus or stomach that may be contributing to your pain.
You would need to alter your diet to reduce the use of foods that would aggravate the
gastritis. This means using small meals and reducing the use of spicy/fried/fatty/acidic foods.
Reducing the use of tomatoes, onions, chocolate and mint is also advised.
Avoid laying down within 2 hours of eating and also
weight loss (if there is any excess weight) would be helpful.
There are different medications that may be used , the
proton pump family of medications may be most helpful (nexium, prevacid, protonix, prilosec).
Vitamin B12 deficiency is not normally associated with these symptoms.
I hope this helps