I have a corn at the side of my little toe, there is dead skin on it, but when i press it on, it hurts. what causes a "corn"?

Corn Protection.: Nothing more than hard skin caused by being compressed, agitated, rubbed and any other verb you can think of. The damage is being done by a toe bone, on the inside, and the shoe, on the outside. These two structures are trapping the skin, in the middle and causing the skin to thicken and harden. This is purely for protection, a kind of armor. The eventual pain helps fend off the further damage.