A pain in the neck because of an inflammation of the throat tissues, this is usually caused by an infection in the respiratory system. But it's often caused by inflammation not caused by infection.
A sore throat due to inflammation of the throat tissues. This is usually caused by an infection in the respiratory tract. But often caused by inflammation caused by the infection.
A pain in the neck due to inflammation of the membranes of the throat. This is often caused by infection in the respiratory tract. But often caused by inflammation which is not caused by infection.