ELI5 Hair - pluck out a hair, then rub the pain away, why does this work?

When I pluck a hair out of my forehead, the area hurts a lot, but I can reduce the pain to nearly zero simply by briefly rubbing the area. Why is this? What is the gate control theory? Why do some hairs grow only grow to a certain length (like our eyebrows), while others grow forever? ... We explain like i'm five! Thank you to the r/explainlikeimfive community as always and in particular the following users whose questions and comments formed the basis of this discussion: notnat3, perry_cox29, real_shadowave, snekcharmer123456789 & storeoh To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Join us on Twitter: https://www.twitter.com/eli5ThePodcast/ or send us an e-mail: [email protected]