Social pain is that jarring pain you get, in your chest, stomach and head, from painful social situations; like rejection, mockery, criticism, being jilted, being pushed away from a group. Have you noticed that physical pain is quickly forgotten. I can't remember how childbirth felt, and many people can't remember the pain of a broken limb. The worse the physical pain, the less we remember, and even mild pain is hard to recall. I can still remember social pain from about age six.
Social pain is very different. We not only remember it very easily but we also experience it fully every single time. These are the memories that make us cringe and hurt. We can even get social pain from empathy on seeing someone else being rejected cruelly. It can play a key role in anxiety disorders and depression, even suicide.
Is this your experience of social pain? Do you feel it when you receive constructive criticism?
It may be evolutionary. If a group points out an individual as an outsider, that, on a primal level, indicates a life threatening situation, so the response is valid. Humans can only survive (as hunter-gatherers) in groups. In the past a lone human was a dead human. We are technology and culture dependent and that requires other people. Hence the social pain when other humans push us away or identify us as "others." Like with sexist, homophobic and racist words.
It's not the word itself, its the message of the word, that you are an outsider and not in the group. This sends the brain into a "life threatening danger" mode. Words are stimuli. When we apply an associated intent with those words, it triggers an associated response. This means that response is dependent on numerous factors, primarily environmental. If the individuals within a person's environment put an associated social taboo or derogation onto words, then that is how they will respond to those words. "Meaning" to the words is just more words with associated response. The individual gives the word meaning, and in turn, gives it the power to trigger physical response depending on its neuronal association. Even if you educate people to be less hurt by words and emotions, there will always be a breaking point.
I am a loner, not one to socialize into groups. But there are times when I have absolutely no friends and no community due to my reclusiveness and at those times my social pain and anxiety heightens. I don't need an active social life but am happier if I have a loose community I am part of.