Actually, I've kinda used the reverse to my advantage. Like, I'll be somewhere and my foot itches like crazy but I don't have the chance to take my shoe off or anything to scratch it. So I just scratch my arm and the itch goes away. Weird, I know.
I do this too! haha And it works for pain too: if your foot is killing you, pinch yourself really hard on the arm and you'll forget about your foot. Of course there's the side effect of the whole being in pain still thing.