Causes of pain in the sternum may include acid reflux, visceral hypersensitivity in the esophagus and musculoskeletal abnormalities in the chest wall, according to the State University of New York at Buffalo. Sternum pain may come from costochondritis, anxiety, trauma and injury, notes Mayo Clinic.
Pain in the sternum, or breastbone, usually occurs behind the sternum and is classified as noncardiac chest pain. The most common cause of pain in the sternum is acid reflux, when stomach acid backs up into the esophagus and then causes heartburn and chest pain, notes State University of New York at Buffalo. Visceral hypersensitivity of the esophagus means patients may feel pain after small changes in the throat. This sensitivity originates from nerve endings near the esophagus. Strains or sprains of the chest can also cause pain in the sternum.
Costochondritis is a condition caused by inflammation of the cartilage that connects the ribs to the sternum, according to Mayo Clinic. Pain from costochondritis mimics that of a heart attack in some cases. Costochondritis has no known cause as of 2014, and treatment usually revolves around easing a patient's pain until the condition improves on its own.
Strained chest muscles from excessive coughing or from an injury may be minor causes of sternum pain. This pain can be exacerbated when a doctor touches a tender area near the sternum. Sudden anxiety coupled with rapid breathing may also bring about pain in the sternum, notes Mayo Clinic.