Been there; done that. I'm not sure what it's all about but that is a completely normal turn of events for me. I guess it's about all the increased blood flow to the joint during the active phases that help decrease the soreness and then when you are not moving it as much the pain surfaces more.

Question is whether that's a sign something needs to be changed. What I've noticed during periods of just three days to a week off I'll start getting aches and pains from previous problem areas and then I'm fine once I'm back to it. If I am forced into more time off I've noticed that the pains do subside on their on even if I don't work out again. Not that you can do anything with all of that it's just what I've noticed with myself.

However I never take a week off with NOTHING. Even when my health is bad I'll at least do my mobility drills and maybe some very light high rep "technique" work. Keep moving even if it's in very small ways.