Recliner chair. Another suggestion is to sleep in a semi-recumbent position which is the position of a typical recliner chair. Either you can use sleep in a recliner chair or one can use a bunch of pillows to recreate that shape in your own bed. Many patients with shoulder pain of all types report that this position is well tolerated. Good luck.
Ice and antiinflamat. Besides pillows and a recliner, ice and take antiinflamatories before bed. If none of these help you need to be evaluated for a rotator cuff injury or shoulder arthritis.