I've just started working in a shop, and I don't get to sit down at all apart from in my break (if I work 6 hours, I get one 15 minute break). The standing really hurts my knees, which I wonder if that's normal in itself? As everyone else at work complains about their feet, and mine don't bother me, it's just my knees - but anyway, after my first full day working, where I was standing up for pretty much 8 hours solidly, I noticed the next day that the front of my thigh had gone numb. By this I mean the skin was numb, as if it had gone to sleep, but I can still feel the muscle underneath if I press on it. It was still numb the next day, and I worked again today and I have noticed that the numb portion has gotten larger. Is this normal, or should I be concerned?