How chronic pain differs from acute pain?

Acute pain is the pain which you experience immediately after an injury, cut, or tissue damage. It usually lasts for less than 3 months.

Chronic pain is defined as pain that has lasted longer than three to six months,or is “pain that extends beyond the expected period of healing”.
What make chronic pain different from acute pain? Well, several factors. Chronic pain recruits other areas and pain generators over time and become a complex problem. It is like an onion which when peeled reveals one layer after another layer and hence cannot be treated by one treatment approach, one injection or one magic cure.
Then there is this phenomenon of neuroplastic changes in the brain. Under persistent active pain transmission to the brain,a wind up phenomenon is induced. The threshold for pain signals to be transmitted is lowered and additional neurons are recruited to process and “listen” to the pain. These changes cause an enhancement of pain signals and perception and give rise to the “memory of pain”. Fibromyalgia is one such chronic pain syndrome.

Chronic pain of different etiologies has been characterized as a disease affecting both brain structure and function.