Heel pain can be caused by many different problems.  If you were hit by a car it definitely could be attributed to that.  But if you just recently started having this problem, you need to let your primary physician know.  Heel pain can be caused by having a spur in your heel, or it can be something like Plantar Fasciitis.  Until you can get in to see your primary physician I would recommend getting a comfortable pair of memory foam slippers and using a thick gel insert in your shoes that should at least relieve a little of that pain.  Be prepared to tell your primary physician when the pain started, how bad the pain is, and what activities make the pain worsen.  Keep your head up! Good luck and best wishes!