Neck pain after arm injury

Answer 1

  The seience behind this mechanism is very simple and straight when ever there is any injury or pain in the body then the pain in neck or head is always there.

This is because the neurons are working extra to fix the injured area and they need to take the require information form the brain. 

so brain had to pass orders to neurons about the injured areas and besides to contain rest of body.

So there is a possible chance of getting head or neck pain in case of any injury. 

There might be some defected veins which can cause neck pain.