Why does a wound hurt?

Answer 1

If it didn't, you might like to get wounded. Then you would probably die from receiving too many wounds. You would be less likely to have children before dying. A species much like yours that doesn't like wounds would come to dominate the earth. They would probably make up a word for not liking wounds, and call it "hurt". Oh, wait. That already happened.

A wound / injury hurts because of the nerves in the area that has been damaged sends signals to the brain telling it that something is wrong.

This enables us to deal with the problem and stop it from getting infected / worse.