This happened to my sisters honda accord. She was going to turn it off, and it went into teh off position, but wouldnt go back into lock. We tried everyhting, then me being pissed took a can of silicon srpay that i use for my mountians bikes lube on teh gears, sprayed it in (probably not the best idea) and broke it out. Its still hard to get it to turn to ignition but itll break most of the time with out to much work. Hopefully we wont have to bring it in, casue i dont want my sister using my jeep cj-7 when im using my stang

 

lol. You can spray what ever you would like in a FORD cylinder and it wont work. Ok... here it is. You have a ignition cylinder..
Inside of that you have another cylinder held in by a lock ring
Inside that you have 5 tumblers, and 5 springs. The tumblers have a number 1,2,3,4,5
The number of the tumbler coinsides with the cut of the key.
Sometimes the tumblers get stuck, or fall out of position
So the key wont turn
so spraying anything in there will not have any affect on it
Unless it is stuck in youre Honda's case it will help
Silicone spray isnt bad for it, its just better used on rubber and plastics
a WD-40, or PB blaster would help more, then spray some white grease in there. Will help from doing it again.
AND when you get a new ignition cylinder...
You have to rebuild it. It comes in about 6 different pieces
Its take some serious time and concentration, consideering the springs are about the size of a eyelash

 

It sounds like a ignition cylinder to me too. I had a problem with my stang too. I just removed the ignition cylinder added some multi purpose grease inside bottom of the ignition cylinder, In which made the cyl to turn easy. Well if that doesnt work then you may need to replace the whole ignition cylinder with a new one.

Good Luck.

 

or just have your local thief look at it I'm sure he can make it turn