[Aerbil313]

But ironically those people were truly and seriously getting headaches and tin foil really made it better. People get to experience what they believe deep in their subconsious. See the Nocebo effect: https://en.m.wikipedia.org/wiki/Nocebo

Having 2 doctor parents and some amount of experience in the field of hypnosis, I can say these sort of things happen all the time to people.