<human>: I did my first marathon a week ago. I've been running and biking for years, so I'm used to certain types of pains like tight IT bands, but this around the marathon I've been getting new pains.

The pain is on the lower inside part of my knees, mostly on the right but a little on the left too. I can sometimes see a tiny bit of swelling. Cold doesn't help, but heat does. It hurts when I stretch the inside of my legs too.

The reason I'm asking here is that I started to feel the pain more during the taper. It started just over a week after my 30k run. It subsided after I did 18k between the 30k and the marathon. It started to come up again before the marathon, but was gone for the race and most of the week after. It's a week over now, and my knee has been feeling crappy since Thursday. It felt no better or worse after my 8k yesterday.

One last thing. I've only ever had pain on the outside of my knee because of the tight IT bands and I'm a bit of a supinator. Every answer I've seen for this kind of pain was for a pronator who was over training, and they get the pain during or after the run. I've never seen someone asking about pain coming up during the taper. Does anyone have any idea what this might be, or do I just need to keep the volume up and back off more slowly until I reach my off season milage?

Could you distill the essence of the text into 1-3 sentences?
<bot>: If I don't run enough, my knee starts to hurt, and in the wrong place for how I usually run.