[usajdm]

Damn......... I was gonna suggest checking the shift lock out which is used for automatics, but still comes on the ignitions for manuals to.
I know it sometimes can get moved into "lock" position on accident.
But your saying yours is the stock one, so it wouldnt have this switch.

Id still suggest replacing the ignition.
Its really easy to do.

For now, try lightly tapping the key inward.