There are many different types of pain that we experience, but as I've thought about this, they can all be grouped into four main clusters. The many nuances of pain can be represented by the larger emotion. I believe, based on what I've read, that these four emotions are represented by specific chemical response patterns in the brain.
Many painful circumstances trigger all four of the faces of pain. When thinking about pain, it is helpful to examine each of type independently. Understanding my response to the situation can give clues into possible actions I can take to find a remedy.