HELP!! Ignition stuck. Key won't turn

My 2001 1500 LT Silverado Z-71 is acting up. 45k miles.
I can't start the truck.
I put the key in the ignition, and the key won't move in either direction.
The security and auto locking system seem to work fine.
I tried the spare key with the same no good result.
The steering wheel is not locked.
I have tried jiggling the wheel, turning the wheel lock to lock, and rocking the truck. No go.
Then I lubricated the lock cylinder, and heated it up with a hair dryer to see if that would loosen things up. No go.

Any ideas? It has stuck once or twice in the last two weeks, but it didn't seem to be anything serious. A couple of wiggles, and the key came free and the truck started fine. This is much worse.

To complicate matters, my driveway runs downhill away from the house. The truck is backed up to the house, so it may be a b***h to tow, if I can't get it going. (Will I have to have the driveshaft disconnected before towing it?

Thanks for any help.

Regards-David

Try a locksmith before towing it. Sounds as if the ignition key cylinder may need to be repaired or replaced.