why you feel heart in your hands when you hammer a nail into a wooden plank?

this is due to the third law of motion. when hammer a nail, hammer exerts a force on the nail and nail also exerts an equal and opposite force back on the hammer, but the hammer is held by us in our hand that is why the force exerted by nail acts indirectly on our hands rather than on the hamme,.due to this we feel hurt in our hands.