Ford: 99 Taurus, shift lock, transmisson

Question
I have recently started having a problem getting my car into drive. I am pretty sure I need new brakes in the rear the front ones were replaced about 3 or so months ago. It is becoming very hard to to get it into gear from park. I am afraid I am going to get stuck somewhere and not sure how serious the problem is. Thanks for your help.

Answer
is the shifter hard to move or does the transmisson not want to shift?? if the shifter gets hard to move the shift lock could be malfunctioning... (It makes you not be able to shift from park without your foot on the brake) I can go further after I hear back from you...