hi there.

some very good info from musculoman there.

you really do need to see someone skilled face to face by the sounds of things. i, personally, would start with motor control and strengthening around the hip. i wouldnt even start to stretch anything out initially. i imagine you have really poor hip stability with probable hyperactivity in tensor fascia lata, which is the muscle that attaches to the ITB as musculoman described, as it attempts to exert some sort of control over the hip. in some cases there is no point stretching out the ITB if you dont strengthen your glute medius, which is the muscle that should be providing a lot of hip stability.

also musculoman has listed a number of exercises but i would start you off by isolating glute medius in sidelying (google "clam" exercises) to really get this muscle firing before moveing onto any type of dynamic stability or higher level strengthening exercise. its imperative that your exercises are done the right way with good form and are progressed appropriately, this is why you need to visit a good physio.

you need to have your pelvis/hip examined in detail to see what your strength/stability/control is like and what compensatory strategies you've developed that are adding to your problem. only then will you and your physio know what way is right to proceed.