Sacroiliac fracture 1 year ago non displaced had 2 MRI not healed in so much pain hip burning and legs too?

An ununited. Sacral fracture (pseudarthrosis) can be very difficult to bear. If this is not healing one consideration would be treatment with injection of methacrylate to fuse the bone segments together. This can be done by interventional radiologists under flouroscopic/ct guidance.
SI injury. Unfortunately, this is not uncommon after traumatic injury. Understand that fracture occurs along with significant ligament injury in many. Often, it is instability from the ligament injury that results in pain as the bone usually heals. Other consideration is nerve entrapment by fracture or the healing process. If truly an si problem, this can be fused using minimal invasive techniques.