pants rash

yup, here's a long story. I had made plans to vivit a customer yesterday and when I swung by @ 10 to noon.... the front doors were locked. So I had an hour to kill. I ate lunch, but that just took 15 minutes so I really had to come up with something. It's too cold to just loiter so I followed some other people into Old Navy on State. I found some great pants on sale for $14, bought them and then went to my appointment.
So today, I wear the new pants, they have pockets. Pockets are so important to a girl like me. Anyway- by 11am my legs start to burn and itch... by noon I want to go home to take my pants off.... I went into the ladies to check out the situation and I'm just covered in a rash... or is that hives???
So, what is it that could do that to me? I'm not sensitive to anything, I mean, really... I can't beleive the things I'm impervious to...
I can feel the bumps under my pajamas that are soothing me right now...
Don't get me wrong, they are great pants...