Could anyone please explain to me why my vp shunt cord hurts?

This is unusual: The vp shunt tubing should not hurt. In fact, you shouldn't be able to feel it at all (sometimes you can feel a ridge, but should not hurt). I would see your neurosurgeon about this. If there is associated swelling, redness, or fever, consider this an emergency. More on hydrocephalus and vp shunts, read this monograph: http://wp.me/s382os-hydrolog