A physical therapist told me to ice my elbow tendonitis with a dixie cup that I had frozen water in-then peel some of the paper away and rub the ice in a circular motion until the area is numb. It seems to take less time than sitting with an ice pack. I did that to my knee and I got hives. Weird. It might be hard to reach your shoulder that way, you'd probably have to get someone else to do it.