Most people, even children experience unexplained occasional body pain – that is not caused by any injury or trauma. A recent study of more than 1,000 children with a mean age of 11 years who were free of pain at the outset, were monitored over the course of 1 year. It was found that those who suffered regular headaches or daytime sleepiness were more likely to develop unexplained pain than those who did not.
BMC Musculoskeletal Disorder. May 23 2007; 8; 46