Hello!
Thank you for the query.
Such pain right after the meal which do radiate to the back can be caused by gallstones or pancreas disease.
Stomach disease (like peptic ulcer) or
small intestine partial obstruction should be also considered.
Gallstones usually give upper right pain radiating to the back, nausea and vomiting appears. It all happens after a fatty food or alcohol. Similar to gallstones acts
pancreas inflammation.
Peptic ulcers usually gives upper middle
abdominal pain which appears in 1-2 hours after a meal. Nausea can be also present.
Small intestine obstruction can cause bloating, pain after a meal, diarrhea, nausea, vomiting.
I suggest you to visit your doctor and have some tests done. Abdominal ultrasound, blood work, liver tests, amylase, urine amylase, urine analysis and
abdominal X-ray should be done at first. If all tests will be negative, gastroscopy should be also done.
Hope this will help.
Regards.