I am at 9 weeks and just yesterday was realizing I hadn't taken even Tylenol in over a week. I have a ton of stiffness and tightness but no actual pain. Then, BAM! last night I started getting a pain right next to the patella, or maybe behind it, somewhere in that area. Enough that I needed some Tylenol and I'm taking it again this morning because the pain is still happening sporadically.
I don't know if that helps answer your question, I am still all new to this. But I am guessing there are areas in our legs that are either still waking up or responding to more activity. In my opinion, as long as the pains aren't super sharp or enduring, everything is probably fine and we just have to wait it out like everything else. It sometimes helps me to read over my entire recovery thread or my journal that I keep; I will see things I've written that really bothered me at the time, and now I can barely remember them. That helps me believe that some of these pains will also be a distant memory.