I've had issues with the trunk lock not popping from inside, check the strike plate area, if something gets wedged in there it makes it only accessible through the key. I think there's a little switch, try flickin it to the opposite position.
I have an 03 lx. When it gets really cold, the driver's lock won't work, but all the others do. Does anyone else have this problem? Once i drive the car and everythign warms up it works, but i hate using the key.