Left back side of leg pain also noticed left leg is shorter?

Pelvic Tilt. Only way to know true leg length is x-ray study called scannogram. Sacroiliac joint dysfunction (hypermobility) explains both pain pattern & short leg sign. For more information about this topic see my chronic pain board at quora.Com.
Could be from back. A proper spinal exam is needed to check for any curvature pathology. A true limb length discrepancy is achieved by an absolute ct scan. Your pain in back of left leg could be stemming from lumbo-sacral area of spine causing a sciatic like pain. In addition to having your back looked at, i would add a otc heel cushion to your left shoe and see if your pains are alleviated.