Definition of Somatoform pain disorder:

Pain disorder is persistent and chronic pain at one or more sites in which psychological factors are thought to play a role.

Causes, incidence, and risk factors:

Pain is one of the most common reasons that people seek medical attention. In pain disorder, suffering is so severe that it impairs a person's ability to function. However, the pain is thought to be related to psychological factors such as stress or unconscious conflict. Individuals with this illness may have other medical problems, although these fail to account fully for the pain.

Unfortunately, pain that is "psychological" in nature is often stigmatized both by medical professionals and the general public. A poor understanding of the connection between mind and body can lead to the misperception that if pain has a psychological cause, it isn't "real" and should be able to be controlled without medical or mental health treatment.