I have no idea if it will actually help your situation or not, but I had a similar problem where sometimes I'd have to jiggle the key around to get it to turn sometimes.

I lubricated the lock and it's been fine ever since. There was some buildup or something inside the lock that was jamming it up sometimes.

You want some sort of dry lubricant and you absolutely 100% DO NOT USE WD-40. You can probably find a "lock lubricant" at a local hardware store.

Might help, might not. Worth a shot.