Ok well I think I hit the nail on the head before you even said it was at a shop... what else could it be? Maybe they have a new detail guy who just doesn't care. I don't know.. but sounds to me like you entrusted it with someone, only to return and have something going wrong... I mean it's not good to jump to conclusions.. but when you examine all the options, what else could it be caused by? I'd pull the tire off and take a look. If there's a definate flat/bald spot, someone is at fault.