1998 Saturn won't shift out of park

My '98 Saturn sometimes won't shift out of park. The shift lever wil
not move even with the button pushed. Eventually it will suddenly mov
easily. What could be the issue

 

Most of the automatic transmissions have an solenoid activated pawl that
keeps the shifter locked in park unless two conditions are satisfied:
1) Foot is on the brake.
2) shifter release button is pressed.

If the brake lights are not working properly, this is the first thing to
check.
With foot on brake and pushing the release button, you should hear a click
of the solenoid activating and withdrawing the locking pawl.
When the shifter eventually does move, is it smooth (ie is it a shift
linkage issue)?

Check the owner's manual. There is usually a section on emergency bypass of
the shift lock. I don't recommend this as a fix but only as part of
diagnosing the root cause.