Extreme Bouts Of Night Sweats, Chills Since Back Surgery. Causes?

My husband just had a 5 hour back surgery on 1/3/13, came home the next day, and has been experiencing extreme bouts of night sweats and chills since then, along with other localized spots of pain seemingly unrelated to the surgery (in thigh, enkles, etc).. he had been on a morphine drip the night after surgery, and was prescribed oxycontin 10 (1 every 12 hours), along with norco 10-325 (1 every 4 hr as needed for pain) when he came home on 1/4/13. He had previously been taking neurontin 300mg for leg pain, but discontinued on 1/2/13 before surgery. The extreme sweating is bothersome and he has tried eliminating the oxycontin -- could that be causing it? Should he start taking the neurontin again? Thank you for your help. Sondra