hard to shift out of park

i have a 98 jimmy slt with a 4.3 vortec. lately my gear shift lever is hard to get out of park, it has the button and you have to apply pressure to the break to shift from park. it is to the point where i have to hit the button with pretty good force in order for the button to click and get into gear :banghead: . it doesnt do this in any other gear however, it functions normal then.