There are numerous causes of middle back pain. According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases or NIAMS—a division of the National Institutes of Health, back pain, including middle back pain, can range in severity from a mild ache to a sharp, stabbing pain. The NIAMS states that back pain can manifest suddenly, or it can come on gradually. Middle back pain can be caused by poor posture, traumatic injury and certain medical conditions.
Pregnancy can cause middle back pain. According to the American Pregnancy Association or APA, an organization dedicated to promoting pregnancy wellness, back pain or discomfort is common during pregnancy and is experienced by many expecting mothers. In fact, between 50 and 70 percent of pregnant women will experience back pain during pregnancy. The APA states that back pain can manifest at any point during a pregnancy, although it usually occurs during the third trimester when the weight of the baby is approaching its maximum. Pregnancy-related middle back pain can interrupt a person's activities of daily living and cause restless sleep. According to the APA, pregnancy-related back pain may be caused by the following factors: an increase in hormones that affect spinal ligaments, an altered center of gravity that places excessive strain on back tissues, additional body weight, poor posture and increased stress.
Scoliosis can cause middle back pain. NIAMS states that scoliosis is a condition in which there is a sideways curve of the spine. Scoliotic curves can be S-shaped or C-shaped. The NIAMS notes that, in most cases, the cause of scoliosis is unknown and is referred to as idiopathic scoliosis. According to the Mayo Clinic website, common signs and symptoms associated with scoliosis include the following: uneven shoulders, one shoulder blade that seems more pronounced than the other, an uneven waist and one hip that's higher than the other. If scoliotic curves progress, a person's spine may rotate or twist, along with curving to the side, which causes one side of the ribs to protrude more than the other. The Mayo Clinic website notes that severe scoliosis can cause significant back pain and even breathing problems.
Acute pancreatitis can cause middle back pain. According to the National Institute of Diabetes and Digestive and Kidney Diseases or NIDDK, a division of the National Institutes of Health, acute pancreatitis is inflammation of the pancreas that occurs without warning and resolves several days after treatment is rendered. The NIDDK states that pancreatitis is a life-threatening condition that can lead to serious health complications. The two most common causes of acute pancreatitis are chronic, excessive alcohol consumption and gallstones that irritate the pancreas as they travel through the common bile duct. Common signs and symptoms associated with acute pancreatitis include the following: severe pain in the upper abdomen that extends through the back, abdominal swelling and tenderness, nausea and vomiting, fever and an elevated heart rate. If left unchecked, acute pancreatitis can cause heart, lung or kidney failure.