Well, for the past couple of weeks I have been suffering from iliotibial band syndrome (ITBS). I think it is probably due to a couple of reasons:
1. My right leg is 4mm shorter than my left leg
2. I increased the total distance to 60km per week the week before I got the pain on my knee
3. My legs are not that strong

I have been addressing point 3 by doing strength training, mainly weight lifting and cross training. But could not do anything about the fact that I got it. Today I had a good 9.56km run in the treadmill and I have been stretching a lot and doing a number of exercises to strengthen my iliotibial band. April 22 is approaching quite fast and I feel like I need to do a couple of long runs so tomorrow I am planning to do 30km very slow maybe around 6 min 30 sec pace per km.

I found a good blog post on the strength training exercise for the Iliotibial Band.