When experiencing musculoskeletal pain walking or running, it is usually caused by a biomechanical imbalance in the body. Every time your foot hits the ground a chain reaction takes place, traveling from your foot all the way up to your head. If one of the 'links' in the 'chain' is not working, more strain is placed on another 'link', overloading the area. This is usually when you start experiencing pain. The same principle relates to the ITB Syndrom, there is an imbalance in the body and the ITB area is being overloaded.