Activity

When I had a large jagged kidney stone in my kidney, years ago, the pain in my right lower back was poundingly intense. The pain lead to my writhing on the floor and vomiting.  (That suggests the intensity.)  It hurt very much.

That is a description of the pain.  Steven says that it is not possible to verbally express this.  But there you go.  Pain is natural, not mysterious.  Perceiving colors is natural, not mysterious.  Tasting salt is natural, not something weirdly beyond our understanding.