Suggest Remedies For A Burning Sensation In The Sprained Ankle

I sprained my ankle hiking on Saturday. On Sunday, I visited an immediate care center who took x-rays and stated it was just a bad sprain. I've kept it wrapped in an ACE bandage and air cast and kept it elevated as instructed since Sunday afternoon. I have also been icing the ankle and taking Ibuprofen regularly, but wake up during the night with the heel of that ankle feeling like it's on fire. Why would that be and what can I do to combat the feeling?