Have to agree with Tig, here: you need a REST day! and on the shoes as well. Make sure that you are wearing the proper shoe for your foot and gait by having a pair fitted at a real running store. Don't just grab the newest or cheapest pair of Nike's at Sports Authority. Everyone's foot and gait are different and the correct shoe makes all the difference in the world between a comfortable run and potential lifelong problems. I noticed from another post that you've been losing weight. Congratulations! Weightloss also affects the size of your feet and it usually makes your knees feel better, but if the shoes are now old or don't fit right, they could be causing the problems. I know it gets expensive, but if you are running a lot on hard surfaces, you need to replace your running shoes frequently.
Hope that helps. Take a rest day or two. Your body needs it
Mel