The thoracic spine is composed of 12 vertebrae, which are separated by discs and attached to the ribs. Several conditions can create varying degrees and types of pain in the thoracic spine. Sprains are the most common and least serious -- but sometimes the most painful. Other less common but more serious conditions, such as tumors, sometimes do not generate much pain.

Sprained joints in the thoracic spine are the most common source of pain and can be the most severe. Two types of joints can cause this pain -- facet joints, which join the vertebrae together, and the costovertebral joints, which join the vertebrae to their corresponding ribs. Facet joint pain is usually sharp, limiting your ability to move, while costovertebral pain is frequently described as stabbing. A severe, left-sided costovertebral sprain can mimic a heart attack.

Spondylosis, the wear and tear type of spinal arthritis, is common among adults 45 and older. The early stages of spondylosis in the thoracic spine create an achy stiffness between your shoulder blades, sometimes radiating around your rib cage. This stiffness is typically worse in the morning, but lessens with activity. Later stages of arthritis can irritate nerves in this part of your spine, creating an intermittent, burning pain.

Deep, dull, constant pain can be caused by fractures of the thoracic spine. Osteoporosis is the most common cause because of the reduced bone density, which leads to compression fractures. Trauma from a serious fall or car accident can fracture any part of the thoracic spine, which can result in sharp pain, especially with coughing and sneezing.

Scoliosis is an unnatural sideways curvature of the spine, most commonly affecting the thoracic region. It occurs most frequently in adolescent girls and is of unknown cause. Pain from scoliosis can range from nonexistent to severe, depending on the degree of deformity and flexibility of the afflicted area. If severe deformity exists, thoracic pain and tightness can result from simply breathing.

Ankylosing spondylitis is a chronic inflammatory disorder of the spine affecting mainly younger adult men. It can affect the thoracic region and create progressive stiffness. Spinal fusion can occur in late stages, which often stops the pain.

Infection of the spine -- osteomyelitis -- is a serious disease that can become life threatening without antibiotics. Staphylococcus is the most common type of bacteria that infects bone, causing bone destruction and severe, constant pain.

Cancer is the most life-threatening disease of the spine. This condition often creates a dull, intermittent pain that can become constant and severe with progression. Advanced cancer can spread to the thoracic spine from other sites such as the breast, lung or prostate.