They see chronic pain as any pain that lasts for over a month past the normal healing time for an injury or disease. If a person breaks his wrist there is usually pain for 7 to 10 days. But if after 6 weeks there is still pain, RSD may be developing. Pain is a subjective fact and everyone experiences it their own way. Pain creates suffering and again this is a subjective experience.
Many factors affect how a patient reacts with chronic pain.
The mechanics that cause chronic pain are very complex. Chronic pain may begin as acute pain. As time goes on, substance P is released from the peripheral nerve endings. The inflammatory causes of chronic pain respond well to anti-inflammatory medications. If a peripheral nerve damage leads to chronic pain as in RSD, severe and possibly prolonged dysfunction of the neuroaxis in the spinal cord and brain may develop.