Pain is an unpleasant sensation you may experience. In detail pain refers to a neurobiological signal that is transferred to the brain after stimulation of peripheral or sometimes, central nerve receptors or detectors. The brain assesses this signal in the context of past experiences within your current emotional and physical environment and labels this signal as painful. The brain then activates a multitude of responses: emotional (e.g. crying), physical (e.g. activates muscles to move away from stimulus) and remembers the stimulus as painful to avoid in the future.

An acute pain response is a survival mechanism (e.g. after touching something hot or after fracture), prompting the person to seek help or to avoid further trauma by moving away from the painful stimulus. Chronic pain (more than 3 months, or beyond the expected duration of tissue healing) is more difficult to explain. The purpose of chronic pain is less clear given that there is usually no more risk of ongoing tissue damage. Some chronic pain can be explained, for example an arthritic joint that causes pain when it is moved or compressed. Chronic pain from arthritic joints or degenerate discs is usually specific, localized and made worse with specific actions.

Chronic pain from a specific structure, over time can initiate more general pain causing pain across a wider area. The causes of some chronic pain cannot easily be attributed to an injury to a specific structure. We believe the onset and causes of this type of chronic pain is found within the context of past experiences and beliefs, as well as the environment of the initial traumatic event e.g. the pain presentation after an injury that occurred on the sporting field can be different to when injury occurred at work.

Sometimes your response to pain can lead to the activation of an overprotective and overactive neural response. Over time this overactive neural response leads to formation of abnormal nerve connections in the central nervous system that continues to send pain signals to the brain. Chronic pain system activation leads to negative emotions that further amplify the pain experience, and also various protective mechanisms that manifest as fear avoidance behavior. Fear avoidance behavior presents as reduced movement (avoiding potential painful movements) and overactive protective muscle action. This leads to people avoiding everyday tasks or actions because they fear more pain. 

Thus, it is clear that chronic pain is more than just a physical or central (brain) experience, but it affects the whole person and their social network. Treatment strategies for chronic pain should focus on the physical (a specific pain focus), psychological, and social environment of the individual.