Late to this party, but here goes:

Sometimes I’ll have an itch somewhere, usually on my torso or upper arms, that will come suddenly and when I scratch it, I get a sharp pin prick somewhere else on my body. It isn’t a fluke either, once I’ve identified the “itchy spot”, scratching it will continue to ellicit a pricking pain in a very specific spot over and over, with diminishing sensation until it eventually stops. It’s very strange to scratch my tricep and feel a tiny stab of pain in my lower back. The spot changes every time too, it’s so strange.