hey op, get in the car, start it up, and then try and turn the steering wheel all the way to one side of the other.. if the squeling gets really bad while you do it, simple fix.. it's just a lose belt, in this case a lose power steering belt..
i'm not a pro on chevy motors so i'm not sure if you have a serpertine belt that controls everything, or if you have several belts that control only a few things each..
you could also simply find the belt, and when the cars not running, push down on the belts to see if they feel lose to the touch.. they shouldn't have any slack in them at all, so if you feel it move pretty much 1/2 or more, you know it's lose..
if it's not the belt(s) it could be any number of tings like a water pump going bad and a bunch of other shit..
again, my best advice is to find a trustworthy mechanic, yes c/n, i read your post, lol.. while there are tons of shitty mechanics who will rip you off at every chance they get, there should be one or two locally who aren't as bad as the rest.. do like sshz said, talk to a family member or two or three and ask them who they take their cars to and if they like them or not.. word of mouth is a great way to find a decent mechanic imo..