Here is an excellent article that helps explain chronic pain. The central nervous system (CNS–brain and spinal cord) can become “hypersensitized” following an injury, trauma, and/or period of chronic or severe stress, in ways that perpetuate, exacerbate, or distort pain, both from any initial injury, but also from normally trivial or benign sensations, such as light touch, massage, or exercise, or even apparently “spontaneous” pain with no identifiable cause. An extreme example of CNS hypersensitization is phantom limb pain–the limb is gone, but the person still experiences pain as if it were there.

Acupuncture is one of a number of therapies that has been shown to decrease pain hypersensitivity and help reduce or manage chronic pain (others include hypnotherapy, biofeedback training, cognitive behavioral therapy, counseling, meditation, and other stress reduction techniques.

I encourage everyone–patients and their care-givers and family members, and medical professionals alike, to read this article to better undertand pain in ourselves and in our fellow humans suffering from pain. http://www.instituteforchronicpain.org/understanding-chronic-pain/what-is-chronic-pain/central-sensitization
http://www.instituteforchronicpain.org/understanding-chronic-pain/what-is-chronic-pain/central-sensitization