Truck wont go into park

[crimespree]

Here is the problem, i went into the store the other night, put my truck into park, paid for my purchase, and when i got out my truck was 10 feet back from where i left it. it had rolled 10 feet without me even knowing it. my column is a little out of whack but you can feel it when you pull the shifter go into each gear position, event though the indicator is always showing reverse. is there a way i can adjust this to where i can park on a hill without fear of destroying someones property, or even worse? please help so i can take my truck out without paranoia.