Back pain after eating usually has the following two causes: 1. Gallbladder inflammation and gallbladder stones. When the gallbladder suffers from stones or inflammation, there will be a strong contraction of the gallbladder when eating fatty food, and there will be reflexive back pain. The pain is more pronounced if the gallbladder stone is blocked in the common bile duct or the common hepatic duct during contraction when eating fatty foods. In this case, ultrasound and CT examination should be performed to further confirm the diagnosis and treatment. 2. Pancreatitis. In the case of pancreatitis, the disease will flare up after a binge drinking or overeating, and then there will be a striped pain in the back, and a CT or ultrasound or MRI should be performed to further confirm the diagnosis. In addition, blood and urine tests and blood and urine amylase should be done to further confirm the diagnosis and treatment.