Why is that often when you have an itch on your back and it gets scratched, the itch seems to move to another location on your back, requiring additional scratching?
I’ve never noticed that, but I’d guess that the itch hasn’t actually moved. What you’re probably noticing is an itch that was already there, but was not as urgent as the one you just scratched. Once you’ve scratched the strong itch, the weaker one comes to your attention.
To get to the other side?
What happens to me occasionally seems to be a “phantom itch.” I scratch at a place that seems to be itching, but it doesn’t help. Then I move over a few inches and scratch there, and the itching stops.
Maybe I’m just wired up wrong.
That happens to me too. Many itches are apparently caused by histimines in the skin. Taking an oral antihistimine seems to help especially well with these phantom itches.