Here the problem I have been having. I try to run 3-5 times a week and have noticed that when I get towards the end stretch of my 4 miles my leg starts to have pain in it. The pain seems to be in the front part of my leg in between the knee and the ankle. It is only in my right leg so I was wondering if I have that problem where one leg is slightly longer than the other? I have no problems with shorter distance running or walking. What to I do to fix this problem? Any input is appreciated.