Thank you Fazah,
Lubing the Latch from inside and outside with door stuck shut worked for me.
While your solution did not allow my door to open, it DID have me focus on the latch instead of the lock/unlock slider! I sprayed silicon lube in towards the latch from the inside and the outside, THEN the door WAS able to open. Woo Hoo!!! I then sprayed the latch repeatedly with silicon while cleaning as much grease and dirt as I could from the latch and with the handle held up, I moved the latch open/closed many, many times. I also sprayed and worked the inside lock/unlock slider, the pull handle and the pull handle on the outside too. And for good measure, I repeated the same procedure on the other side.