Weird Knee Pain

Question
I just finished my 3rd marathon of the year on 10/4 and both my knees hurt terribly afterward, the left more so. I took a week off and then resumed training for the Vegas marathon. My left knee will feel fine until about 6 miles into a run and then I will get a tight pulling feeling behind my knee (where the leg bends) from there the pain will move to the outside of my knee cap. It can get very painful causing me to stop running and limp home. However within a hour of stopping the knee feels better and there is no pain anywhere. I ran a very slow, easy half marathon this last weekend and when I started to feel the tightness I lubed the knee up with Tiger Balm and it seemed to help a bit. I really want to do the Vegas marathon but also don't want to risk a permanent or chronic condition. Any ideas as to what it may be and maybe how to help it get better? Shoes are the right fit and not over worn. I run on asphalt and trails. I have been running for a little
over 3 years now

Answer
Michele,
First of all you are running too many marathons. Marathons are tough to run and on the body. You should concentrate on 2 per year. If you do more, you are either not training properly or resting properly afterwards. One week off is not sufficient....it can be  as long as you have some easy weeks afterward. However, you go right back to training. You clearly have an injury and continuing to train on it where you have to stop, or in the times it doesn't hurt, you run on it is only going to exacerbate this thing. Take 14-16 days off, stretch, lift light weights, take ibuprofen and then start back easy.

Ryan