There are a few quick and dirty things you can do if you don't take it to an LBS to check the alignment. Take some measurements of the chainstay, from the BB, to see if there is a pretty obvious difference. Install the wheel and see if the rear derailleur is parallel with the cassette or is it at a slight angle. If the derailleur is parallel the hanger/dropouts might be tweaked. If you do file, alter the non-drive side.

John