This is odd...
There can be so many variables, it's hard to say if it's related or not. I take enbrel on Sundays and mtx on Wednesdays, figuring the difference in days should level things out. I still tend to have more achiness on Thursday/Friday, but I think it's related to the middle of a workweek vs the mtx. Hope you feel better.
I think your reasoning about the 'big' pad going away causing pain makes sense. I always 'crunch' very loudly when my inflammation first goes down, especially my neck. Sounds like rifle shots in there. Most noticible for me after a pred pack to knock a flare down. Louder crunching does not hurt me, but that maybe cause I'm so nutz from the pred I'm not registering pain.