<human>: Hi all,

I started running about 2.5 years ago and after the first few months had extreme knee pain. I usually ran outside, still with pain, but I can remember running on a treadmill and my knee hurting so bad after, I couldn't get into my car. It was probably ITBS. I quit stretching and the pain went away.

Flash forward to today. For well over a year, my running schedule was three 6-milers during the work week with a longer run on the weekend (9-12 miles). I started training for an upcoming marathon and my plan has taken me from 10 miles, 11, 12, then 14 this past weekend. Fourteen has been the longest I have ever run. In all of these rungs, including the earlier schedule, I didn't experience any knee pain nor did I stretch.

I ran 4 miles on Monday after the 14 miler on Saturday. My knee was killing me. I decided to stretch the knee Monday night and will do so again tonight. It is definitely tight in my knee area. I'm scheduled to do a 7 mile run tomorrow, but am worried about what may happen pain wise. Further, my training schedule has me doing 16 miles on Saturday. I see this as a huge hurdle to cross - if I do the 16, I feel like the rest of the training will be smooth. 

My question is: should I rest until my knee is 100%? This may sound like the obvious thing, but I should add that Saturday afternoon I volunteered and had to be on my feet for about 4 hours (after the 14 miler). Will sitting out a week or two impact the marathon (its in early December)?

Can you give me the gist of the text in a nutshell?
<bot>: knee is injured. Stretch it, or not? Wait it out, or not? If I wait it out, how will it impact marathon training.