Question on Yoga and pulled shoulder muscles

I am new at Yoga. My instructor has not said much about breathing except not to hold your breath. During one stretch, I felt like I pulled a muscle in my shoulder muscle. Please advice.
(12 Apr 2007)

First of all, there is seldom any connection between holding one's breath, during Yoga practices, and pulling a muscle. If this happens, it should either be in the chest or abdominal muscles.

In any case, I suggest you take it easy for a couple days and , when you resume your practices, don't strain the affected shoulder. Meanwhile, apply warm fomentation or an oil or balm specially formulated for this purpose.