I can finally help someone on the forum, so excited!!
I had intermittent problems with the lock on my drivers side door for a long time, I got fed up with it when I finally ran into the exact same problem youre describing. I Got so mad that i punched a hole in my plastic door panel... not one of my proudest moments
I decided that I was going to figure out the problem, no holds barred. Take apart every last little thing if i have to. Heres the lowdown:
Inside the actual doorclasp (metal part that clips and holds the door closed) Are two plastic pieces that pivot (place the palms of your hands together, and slide your fingers back and forth on eachother, and you'll get a good rough idea of how these pieces move). One of these plastic pieces is connected to the actual clasp on the door, and when it pivots, it opens. The other plastic piece is connected to the handles (both inside and outside), and when you pull on the handles, it makes this piece pivot.
Now, heres where the lock comes in to play: Actuating the lock moves a small pin that mechanically connects these two plastic pieces together. If its "unlocked", the pin is engaged, and the two pieces essentially move as one. When you pull your handle, the door opens. When its "unlocked", the pin is disengaged, and pulling the handle moves the first plastic piece, but does not move the second piece, and thus does not open the door. This Is why you can pull the handle and it feels a little "looser" if its locked... but it doesnt do anything.
HERES THE IMPORTANT PART! The place where the locking "pin" engages these two pieces is fairly small and has tight tolerances. The problem is this: When one of those plastic pieces is even slightly rotated (if the door handle is pulled ever so slightly for example), you cannot slide the pin into place because the pieces dont line up. Thus, you cannot "unlock" your door, because the pin is jammed. Anyways, I typed all of this to say: Your doorhandle connecting rod is most likely just slightly too tight. A telltale sign would be the lock rocker seeming to be kind of jammed... It you can push on it but it wont go fully to either position.
In order to fix, your probably going to have to get yoru door panel off. You can do it without opening the door, but it does kinda suck. Once you do that, figure out which direction each one of the door handle rods actuates in, and try and give htem a little slack. This will allow you to at least get your door open, which is a great start. Then, to permanently fix the problem, give those rods a little more slack by re-attaching them a little farther down. As I recall, I had to bend the rod for the outside handle just slightly. That one goes wayyyy down to the bottom of the door, and then way back up, in order to go around the window. Its kind of in the shape of a V, and I had to tweak it a little to get it where I wanted it.
After I did this, my door has worked perfectly ever since. Theres still a hole in my doorpanel though
Sorry this was such a book, but I was very proud of myself for taking EVERYTHING apart and figuring out the fundamental problem that was pissing me off so bad. Hope it helps