Driver's door won't open from inside or outside
 

I have a 2010 Chevy Malibu. I walked to my car on my lunch break yesterday and the driver's side door was slightly open. I assumed I just didn't shut it all the way.

I got in my car and shut the door like normal but when I got to my destination, the door would not open from the inside or outside. When I got home that night, I called a locksmith to open it, hoping that something just got stuck in the latch and it would be a one-time fix. The locksmith would not open the door due to liability issues in case something broke.

Any idea how I might be able to get the door open? If I do end up having to take it to a shop, any idea what it will cost me? Thanks!

to confirm: it not fully closed. the seatbelt is not caught up in the latch?

that is a tough predicament. I have had a couple of theses on various models. In those cases i had to pull off the inner door panel from the inside. This may indeed crack the inner door panel. Inner door trim panels are very expensive new.
my advise to you is to take it to either a body shop (body shop guys are pretty clever when it comes to this) or automechanic and have a professional deal with it.