Do you mean that the steering wheel "locks" when you turn the car off and take the key out and turn the steering wheel in any side a bit, and you cannot turn the key in ignition lock then? This is a perfectly normal thing and it happens to me every time i move the steering wheel. To be able to turn the key in the lock again, you HAVE to tilt the steering wheel together with turning the key, otherwise you cannot turn the key.
But, if you do not touch the steering wheel after you turn the engine off, and you have that problem, then it's something i cannot help you with
