What Causes Ankle Bone Swelling With Pain And Limping After Rod Insertion?

hi, i have brocken my tibula and fibula a good 2 and a half months ago now. The surgeon inserted an 8mm x 320mm rod in my fibula from ankle to the knee. According to the medical certificate i should be back at work now, but i still have a limp, pain in my ankle and cannot bear any weight on the front of my foot, hence the limp. After many attempts at seeing a doctor and not having any answers could you please explain to me maybe why I cant walk properly and the outside ankle bone is still so swollen? would be much help
regards... wayne