I had a question for anyone who runs or exercises...occasionally when I run, when I hit the 18min mark my thighs, back, stomach and butt itch so bad...it is so bad that I could literally scratch my skin off and not get relief. Sometimes I leave very bad scratch marks...if I don't scratch it I would literally faint from the pain of the itch...does this happen to anyone else? It stops itching in a couple of minutes if I stop running...but if I keep going it gets worse...this is really bad since I run marathons...when I train I can't keep having this kind of hiccups.