I had severe shoulder pains this week from sleeping also, though luckily I didn't develop bursitis. It took a good week for it to go away...the 3rd day into the "injury" I did some heavy sqts anyway. It was bit painful at first but it went away as I progressed into the workout. After yesterdays workout, which involved quite a bit of pressing movements, my shoulder feels fantastic today even though it was giving me some problems during the workout (especially with benching). So unless the problem was diagnosed by your doctor, I'd keep doing some light workouts.