First off: I'm an idiot, so don't listen to me. I tear muscles quite frequently. Partly genetic, partly obsessive behavior.
Germane to this topipc, I've torn a pec three times so far, last time a few weeks ago. So for better or worse I do have experience.
What helps me in getting back quickly is GENTLE stretching. The absolute worst thing to do is to immobilize your arm and shoulder now. Not only will inactivity not help the healing process, it will also shorten your muscle, mess up your shoulder posture, and set you up for poor form and other injuries later. I do very light, but very frequent, stretches. It should not hurt, but it's okay if you feel a
slight pulling sensation. I'll do that dozens of times per day, for a few minutes at a time. No bouncing during the stretch, unless you hate having a pec. At night I'll go to sleep on my back, and will put both arms over my head. At first with my hands on top of the pillow (if pain allows), later graduating to hands under the pillow for more stretch.
Second would be doing a shit ton of overhead work. That has allowed me to get back into the game with minimal losses every time. That, and back work. For me pullups are painful after a pec tear, but rows are fine. In fact I think it helps with my form: a pec tear helped me to stop rowing with bicep pull, and learn to focus on pulling my scapulae back.
