Pokemon and Pseudo Locking

Yesterday's 7km run was pretty fun. I decided to try out the new Pokémon app and spent my run commute time chasing Pokémon all over north end Dartmouth. Before I knew it I had covered 6km and it was time to pick up my daughter. I also learned some interesting facts about some of the local landmarks. I'm not entirely sure why some people are so frustrated by the idea of this game, I think it's an excellent way to get people outside, walking, and learning abut their community.
I also had one of the worst sleeps in a few weeks. I woke up at 4am to searing pain in my knee, it had completely locked up and it felt like someone was trying to pull my kneecap off. I rolled around moaning for a few minutes before I got a grip and started breathing slowly while trying to force my leg to straighten. It took a while, especially since as I tried to straighten the knee I had even more pain, but eventually I was able to get my leg straight. Then the back of my knee started throbbing so I pressed my kneecap into the mattress and that helped for some reason. All I can assume is that it was due to the impending rain?
So, of course, I'm googling how to get rid of this pseudo locking crap. I know its the OA, I know it is a result of swelling in the joint. My question is how do I get this to stop? It's not like I can "make sure to move my knee" since I'm asleep when it gets locked. Today I was a hair away from calling in to the office "sick" because I was pretty sure walking would be out of the question. Thankfully I could get up and walk around, and it's slowly improving as the morning goes on. It just sucks. I tried to think practically. If this is due to swelling, then would taking a diuretic help? Is that going overboard? I refuse to just constantly mask the issue with pain killers, since that doesn't address the underlying problem. That said, today it just hurts too much to not take anything. I do have to get through the workday. So far, Google hasn't been super helpful. Every medical site and forum gives advice for preventing this when you are awake, not so helpful since it gets locked when I'm asleep. The search continues.