Most people think of pain as a purely physical experience. A hot stove burns my hand, my skin is hurt, my brain sends a pain signal, Ouch! This sensory feeling is but one source, one explanation of pain. The second explanation is the role of emotions in the experience of pain. Fear and example, for example, amplifies the pain signal. If we are worried about our pain, it hurts more. The more we worry the stronger the pain signal. The brain is a complex interaction between our physical selves and our emotional experience of what our body is feeling, especially where chronic pain is concerned.
To help us understand more about this, Nicola Twilley has written about the neuroscience of pain in New Yorker magazine, here.