What Causes Stiffness And Pain In Leg?

I have a fracture in my 3rd Lumbar, the end of it is broken. It happened 3 weeks ago today. I am still in pain. I have been taking Motrin as adviced by my doctors twice a day for pain and inflamation. I am also wearing my custom made hard shell back brace when I leave the house. When can I expect to be able to start therapy? When will I be comfortable walking and standing for extended periods? Most importantly, when might I be able to ride my horse again? Also, I have been having pain and stiffness in my left leg (the side I fell on). Sometimes I cannot lift it into the car. Is this something to be concerned about? Thanks so much! -Kate