99 Drivers door lock issue
 

So I was trying to lock my jeep last night with the keyfob and I noticed every door locked except the driver door locked. I then tried to manually lock the door from the inside and noticed that the lock button was extremely stiff and took a good amount of force to lock and unlock. Any ideas on what could be the problem?

Try spraying the lock and inside the door locking mechanism with some good penetrating oil and see if that helps. Sometime they get gummed up and stick. I know I had my passenger door do the same thing. I sprayer mine down and no more problems.