If you analyze only two diseases, pancreatitis and cholecystitis, the symptoms of left side back pain are mainly considered to be caused by pancreatitis. Both acute pancreatitis and chronic pancreatitis can lead to the symptoms of left abdominal pain. Moreover, the pain can spread to the whole abdomen. Without timely intervention, the abdominal pain can radiate to the left side of the back. Cholecystitis can be categorized into acute cholecystitis and chronic cholecystitis, both of which can lead to symptoms of right upper abdominal pain in patients. Acute cholecystitis, in particular, can radiate pain to the right shoulder or right back during an acute attack, but does not usually result in left-sided back pain. This symptom should also be considered in the context of other diseases such as lumbar muscle strain, which cannot be accurately diagnosed on the basis of this symptom alone. If the patient’s symptom persists, it is recommended that he/she seeks medical attention as soon as possible to confirm the diagnosis.