What is the nature of pain?

What is the nature of pain? Is it all the same or is the category of "pain" too general to be useful?

There seems to be one kind of pain that is indisputably actual, and that is physical pain, which includes everything from a stubbed toe to the throes of childbirth or the inconceivable agony of a body torn asunder by torture, accident, or dread disease. All pain other than the physical is of a different ilk, which is not to say that the associated suffering is any less "real" to the sufferer, but clearly the source of the suffering is not a physical injury or malfunction.

An example of this psychological pain is the feeling of having been "insulted." If we are referred to as a "FOOL," we feel a kind of pain. What is it about us that turns a simple syllable into a torture device? If I believe I am not a "FOOL" surely another's wrongful assessment cannot reach me in such a visceral way unless my "reputation" -- my image in the eyes of others -- is seen as under attack. If I am truly not a "FOOL," then my own actions and words prove my judge wrong on an ongoing basis, but the part of me that is concerned with such matters, my "self" or "ego," is never quite sure of itself and perceives a threat, which manifests as "insult" or psychological pain. Therefore I lash out, I use all the tools at my disposal -- "knowing" words, dismissive gestures, facial contortions, even physical violence -- to discredit the source of the perceived "insult" rather than to honestly look into the internal process that actually results in psychological pain. In pursuing this conditioned reaction, I miss a valuable opportunity: to deeply enquire as to whether I am, by whatever definition applies, actually a "FOOL!"

Does my world collapse if it turns out I am a "FOOL," or is an honest (neither prideful nor self-hateful) realization to this effect a gift, the beginning of something quite extraordinary? What happens when one clearly observes that which makes "FOOL" an accurate assessment? Once this is clearly seen, does the label "FOOL" any longer apply? Let the word "FOOL" be an opening into enquiry, and perhaps the nature of the whole edifice of psychological pain will become apparent. This is the response of intelligence to "insult."