From my travels in W Africa, especially among my husband's family, I have often been struck by their stoicism with regard to pain and suffering. It's a cultural thing, and it's just 'not done' to groan, whine or cry out. Some African tribes have rather horrifying 'initiation rituals' (circumcision etc) and the poor subject must not make a sound, or their family would be utterly shamed before the community.
This is not to say they don't feel the pain of course, just that it mustn't be expressed.
I could never be that brave I'm afraid.