I had the driver's side door apart to install the SBC lift, but since the passenger side window isn't broken yet, I decided to wait for the inevitable failure before I went to the trouble of the install. When Tom helped me out with the step bar install a few weeks ago, we sprayed white lithium grease down the door to lube the tracks but didn't take the door apart to do it.
It's a good point that maybe the driver's side lock was fouled. If both door locks run through the same circuit loop, it's certainly possible that a loose connector in the driver's side door could disable both doors. Thanks LDub.
It's definately a WAG, but the possibility that came most readily through the cobwebs...
Hope you find an easy fix...and speaking of easy, you don't have to pull the door apart to check the switch connections, just remove the switch cluster...