Whenever I squat I get a huge pain in my neck, it hasn't stopped me yet (for instance, today, I did 275lbs for four reps, as my 5th set, first time ever going that high) but it does bother me after I've worked out. Anyone know what it is? I get it right when I pull the bar off the rack, so I think it's a nerve I might be pinching or something, but I'm not sure. I've tried holding the bar lower or higher on my back, but to no avail. By the way, I don't use a pad on the bar or anything.