What is wrong with my ankle?

Ok, so I sprained my ankle about 3 weeks ago and i went to the hospital. They gave me a soft sock velcro thing. When i went to the doctor because my ankle was still hurting he gave me another soft sock velcro thing! They took x-rays and said nothing was broken at the hospital and the doctor. My ankle really hurts when i walk on it and at the end of the day when i take off the soft sock and my sneaker, my foot\ankle is swollen and has bruises right above my metatarsal bone. I began to think that maybe the metatarsal bone was fractured but the doc says its not. I have been hobbling around my house and the doc says it will take time and that putting on a boot isn't necessary but it REALLY HURTS! So what is wrong with my foot\ankle? Should I wear a boot?