Brief Answer:
Gallbladder problem.

Detailed Answer:
Hello,
Thanks for query.
As per your narration most likely its gallbladder pain.This organ is a sack that collects a digestive juice called bile. It can get infected or get stones, and usually causes severe, intermittent upper abdominal pain on the right side with radiation to the shoulder or back in some patients, which is triggered by the ingestion of fatty or greasy foods.
Loss of appetite nausea vomiting are suggestive of gallbladder stone.

Suggestion
Go for a Ultrasound abdomen asap to rule out gallbladder pathology.
Cholecystectomy laproscopic can be done after that to remove gall bladder.

Thanks!

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Brief Answer:
In that case it can be cardiac also.

Detailed Answer:
hey there,
If gall bladder is not there and pain is not responding to conventional treatment given for Gastritis(Pepto tums and ranitidine) i would suggest you to go for cardiac investigation.

Some times angina(cardiac pain) presents itself as upper abdominal pain and as there is radiation of pain also to shoulder cardiac event should be ruled out initially.Once cleared from cardiac side we can treat it on guidelines of dyspepsia and gastritis.

Dyspepsia, in layman's language is known as indigestion. It is a term that describes discomfort or pain in the upper abdomen. However, it's not a disease in itself. Dyspepsia is a group of symptoms which often include bloating, nausea and heartburn.Take a proton pump inhibitor like Esomeprazole 40 mg twice daily along with a prokinetic drug (eg.Domperidone) for 3 days. This will provide you symptomatic relief from symptoms of dyspepsia (you may need to obtain prescription for this from your local physician).

However initially a cardiac checkup should be done to be on safe side.

wish you great luck.

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