Upper left side back pain can be caused by acute pancreatitis, Healthline says. Although the pain manifests mostly in the upper left side of the abdomen, it can spread to the left side of the back and left shoulder blade.
Pancreatitis, which can cause abdomen pain that spreads to the upper left shoulder blade of the back, is also accompanied by nausea, vomiting, diarrhea and bloating, states Healthline. Those who experience these symptoms should seek medical help immediately. Sometimes acute pancreatitis is caused by other conditions such as cystic fibrosis, Reye's syndrome and Kawasaki disease. Limiting alcoholic intake can help prevent pancreatitis.
Upper left side back pain as well as chest pain, difficulty breathing, jaw pain and nausea can also be caused by a heart attack, according to Health Grades. An individual with these symptoms should contact emergency medical services. Some other conditions that cause this type of pain include a herniated disc, spinal stenosis, injury, cancer and fibromyalgia. If the pain is a resulted of fibromyalgia, the individual also often experiences fatigue, anxiety and depression, shoulder pain, stress, and headaches. Often sports injuries caused by sudden movements, strains and sprains can result in upper back pain. Although herniated discs most often occur in the lower back, they can occur in the upper back as well.