Has anyone ever strained/torn their Deltoid muscle?

I fell and strained/tore my Deltoid muscle in my right upper arm/shoulder about 8 weeks ago. It is impossible for me to keep the arm immobile and I have now, re-injured it several times, most recently today. Does anyone know how long it takes this sort of injury to heal and are there any exercises I can do to help things along?

I am having range of motion issues that catch me by surprise and cause pretty bad and immediate pain. No, I have not seen my doctor, yet, but I might. I am not one to run to the Dr. for relatively minor issues but this is starting to get me down.