I recently injured my knee at work after either lifting or pulling pallets. I feel a slight strain to no pain while up and walking around during the day, but while i'm lying down for long periods of time (e.g. sleeping) I can wake up and my knee is in imense pain, that I sometimes need to jump up out of bed to make go away. It is on the right side of my left knee. There is no sign of bruising, and very slight swelling. Any ideas?