Power door lock woes

[Tin]

I have a 2000 Grand Prix GTP, and yesterday while pulling into my parking space, the auto doorlocks disengaged when I put it in park like usual, but then I heard this grinding noise coming from the rear of the door. This is happening on the driver side door, and it wont lock or unlock with the keyless entry, only when I insert the key. The lock is a bit tough to engage and disengage by using the key. The grinding noise is coming from the part of the door that latches to the post to lock it. Any ideas anybody? Do I need a new power door lock motor?