You tore you shoulder muscle as in you strained it, right? If so, you need more than a week for that to heal. More like 8-10 weeks for it to totally heal up. In the mean while, you should go light on any exercise that requires any shoulder movement or your muscle will never fully heal. I know it sucks to get injured like that in the middle of your cycle. Been there and done that, but it's part of the territory. Just make sure to ice it ed for 20 mins, 2-3 times a day. Remember only time will heal it.