Pains ... seem to be subjective in the sense that their existence depends on feeling them. There is an air of paradox when someone talks about unfelt pains. One is naturally tempted to say that if a pain is not being felt by its owner then it does not exist. (‘Pain,’ section 1.2.)Wittgenstein also has a famous passage:
It can’t be said of me (except perhaps as a joke) that I know I am in pain. What is it supposed to mean—except perhaps that I am in pain? (Investigations, §246.)This is the same kind of observation and it rings true for many people.