Problems pushing button in to engage shifting

Hi Everyone,
Forgive my ignorance on correct car terminology here. I just bought a '98 Lumina LTZ and am having problems (didn't have this problem or notice this problem when I went to test drive it) w/pushing the button in on the "stick" mechanism to engage shifting (i.e. to shift into drive or reverse etc.)--does anyone have anyone ideas as to what the problem could be? Eventually I am able to push it in, but it's really difficult especially when I initially try to drive it--it seems easier after consecutive tries though? And I do push the button in hard. Thanks!

Someone may have spilled soda, coffee, etc... in the center console and got it all boogered up. You may have to remove the console to get at it to clean it up.

I have the same problem with my 98 LTZ on cold (-10F or colder) winter mornings. It has to do with the "apply brake when shifting from park" safety mechanism. I find that keeping my foot on the brake, applying firm constant pressure inward on the button, and gentle pressure backward on the shifter works best. Never had it stick for longer than 10 seconds, so I don't worry about it. I assume there is some sort of electrical solenoid in the shifter that "sticks".