Dani, this may help explain about oxygen and blood to muscles... From Alan Gordon's TMS Recovery Program: The autonomic nervous system is responsible for the great majority of chronic pain conditions. This system controls the circulation of the blood in the body: for example, an increase of blood flow to the cheeks when a person is embarrassed; a physiological reaction to a psychological trigger. The autonomic nervous system can also reduce blood flow to certain muscles, nerves, ligaments and tendons in the body. When this occurs, there is less oxygen available to the tissues, and the result will be symptoms, such as pain, numbness, tingling, and sometimes weakness4. Various studies have supported this hypothesis.