When you pull your hair you damage the nerves on your head causing you pain but when you cut your hair don’t hurt because your hair is not alive. Hair is made out of a protein called keratin. Only the root of the hair—the part that grows inside the skin on your head from tiny holes called follicles—is alive and growing. So if you pluck out a hair by the roots, it hurts. But trimming or cutting your hair is painless.
