Help my car wont shift into gear

My 1998 mercury grand marquis will not shift into gear from the park position once it is started. If the car is put into neutral and then started it can then be shifted but once put in the park position it again can not be moved. What is causing my car to get stuck in the park position?

Hay I need help please my car broke when I put it in reverse then when I tried to put it in drive it got stuck in neutral and the gear shift would just slide up and down. Luckly I broke down in front of a mechanic and he said something that connects to my transmission came disconnected I just need to know if you would have any idea of what the part was called I know it started with a D well if you have any idea of what the part is and possibly the price just let me know thank