I too have facet joint problems, looks like facet joint athritis. I haven't run since March last year. An MRI scan shows all sorts of problems, but the main source of pain they think is from a lower facet joint RH side, almost certainly caused by a few falls on my back a couple of years ago. That said it is gradually getting better compared to 9 months ago when I couldn't even cycle as my back hurt when standing up on the bike.
I'm presuming that I will never run again, though I did manage some uphill and flat shuffling recently at The Hebden without adverse effect.
I'b be interested to know if anyone ever had something like this and managed to return to running?
I've been offered a temporary block via injection to see if that joint is the source of the pain. If successful then they can perform denervation on the joint to kill the nerves to stop the pain. Lasts for about 18 months as the nerves grow back. I'm tempted to have it done but am concerned that running on it without feeling pain in the joint will cause further damage to the joint.
At least I am cycling and walking pain free now and don't need painkillers.