To what extent are the hadiths that link not being afflicted with headaches or fever to entering Hellfire authentic, and does my not being afflicted with headaches mean that I am one of the people of Hellfire?

A group of scholars have authenticated the hadith: "Whoever wishes to look at a man from the People of the Fire, let him look at this one." The hadith certainly does not mean that whoever does not suffer from headaches is from the People of the Fire. Rather, what is intended by this hadith and others similar to it is that among the signs of the people of faith is the frequent affliction of their bodies with illnesses and pains, as a purification for them, an expiation for their sins, and an elevation of their ranks. As for the disbelievers and hypocrites, it is the opposite. This is generally and predominantly the case.