Pain is a word every human being can understand. Except those with congenital insensitivity to pain there is probably no human being that has completely escaped the perception of pain. Pain is an unpleasant feeling related to a physical aggression compromising the integrity of the body. It also has an emotional component that may be weak or strong. The fear of pain may be as disturbing as pain itself, as many a torturer knows and uses.
Veyckemans, F., & Rodenstein, D. (2013). Lord, deliver us from pain. The European Respiratory Journal, 42(2), 297-298. https://doi.org/10.1183/09031936.00005213 (Original work published 2013)