My swollen knee

Patient: I dislocated my knee in a car crash 2 years ago. a couple of months ago i sprained it in the same place as the prior injury. i went to the hospital and they told me to keep kneebrace on it for a few months and see how it feels afterwards. i went to the doctors about 2 weeks ago and they told me to rest it and not to move a whole lot. now i have swelling and throbbing pains in the same knee. now even when im laying in bed i get the same throbbing pain in the same place in my knee without even moving. what should i do?