How exactly is referred pain felt, and what is its biological purpose?
Is it anything to do with “sympathetic pain”? I am asking because during wisdom tooth twinges I find that the back of my head, and occasionally my shoulder feels the same pain.
I don’t think it has any biological / evolutionary purpose; as far as I know it’s caused by pain-transmitting nerves from different parts of the body joining the spinal cord at the same place; correct me if I’m wrong but it’s literally a case of crossed wires. So you could have acute angina, but feel it in your arm instead of your heart, as the brain gets confused as to where the pain message is coming from.
Don’t know anything about “sympathetic pain”; perhaps your muscles tense when you get the toothache, and that causes the muscle pain.
Cool! 