Been running "seriously" for 2 years, doing OK. Completed 10k's, HM's and 3 marathons. I ran Stratford Marathon in April and ever since when I run my action is all wrong, which leads to discomfort in my right calf/hamstring, I have tried resting, lots of stretching, been to see sports physio twice and they have diagnosed I am running lobsided, left leg longer than right due to problems in hips/pelvis. Been following stretching/core programme and I am x training to try and keep fitness. But it is not any better, what I cannot understand is I feel no injury and how suddenly have I a problem with hip/pelvis. Anyone had a similar problem and/or advice.