Restore full non protected mobility to L4 Wikipedia reference-linkfacet joints and by doing you will quickly find reductions and ultimately elimination of this referred pain issue( often erroneously referred to as ITBFS). Best method is known as Continuous Mobilisation, this may take up to fifteen minutes at each L4 facet joint. In some case it may also be necessary to stretch and/or massage piriformis, which commonly assumes a higher state of tone with irritations at the L4 nerve root. Mobs at L4 however will restore a normal state of tone to this muscle , whose anatomical position close to the exit foramen for a large nerve bundle makes it a common corrollory to referred pains to the lateral thigh with L4 hypomobility.
Stop treating the thigh/leg and concentrate your efforts on the nerve irritations causing this problem. Ideas mentioned above in relation to altering seat position, and other biodynamic parameters may be useful in the context of reducing spinal protective behaviour, thus adding to a percieved benefit at the site of referred pain in the thigh/leg.
It is good to remember that all pain happens in the brain, also that all pain can be said to be neural in origin and effect. The only valid questions then are about where and how are nerves involved.