I think what can happen sometimes is that our daily situations, may lead to a "blast of adrenal cortisol" one day here or there,
which may have anti-inflammatory effects and blunt symptoms some if those are inflammation based. (stress mediates cortisol release...good stress can do it as well as negative stress).

It is also possible that distraction, changes the brain that day, perhaps giving you some endorphins that blunt your pain.

I also think that sensory overload on PN affected areas, can cause cramping and other nasties. In summer when I have only the fan on, I put it blowing across another part of the room, where it can bounce off the walls and some can go out the door.
If blowing on my legs at night, I can have terrible cramps.
When it is really hot I put on the portable A/C , but it makes alot of noise and bothers me that way. So I use a fan alot...but very very carefully.

I think we all here have good and bad days/nights. Comes with the chronic nature of the beast.