2001 Aztek Ignition Key Won't Turn

I have a 2001 Pontiac Aztek and the ignition key (with chip) will not turn in the ignition, we only have the one key any suggestions? Do you think it's a problem with the chip in the key, or ignition or security? It's a two sided key and I've tried both ways. The key will lock and unlock the drivers door. The car is parked in the driveway with a slight decline and the front wheels are straight. I can't turn the key or get the steering wheel to move more than 1" either way, also it will not move out of Park. The key/ignition was working fine 2 days ago.