After 6 weeks w a cast on my right ankle, my leg is set free. Injury: broken ankle. It still hurts. Y?

Stiffness. After being in a cast for six weeks any joint will be stiff, and weak and can cause pain. Assuming everything healed correctly time and some therapy can chelp restore motion and strength which will help with the pain.
Broken ankle. Takes bone 8 - 12 weeks for bone to heal. It then takes additional 1 - 4 months for the soft tissue to heal and reach 90% improvement.