I did a search on shoulder injuries, but none I found really matched how I feel.
First, a little background.
I'm 22 years old, 5'11", 174lbs, ~19% BF and I've been training for a few years off and on, and I was just starting to lift again after six months off(rough semester) when I injured my shoulder. I performed the first day of big boy basics about a week ago and on nearly every exercise I had slight right shoulder pain, and didn't finish the workout(didn't want to hurt shoulder further). Later that day I went to work(auto parts store) and had to lift several car batteries onto the counter(just below chest level). I felt no pain while lifting them.
The next day, in addition to soreness, I had pain in my left shoulder.
Fast forward to a week later. I haven't lifted since the shoulder pain day and shoulders have felt normal again. Yesterday at work I had to lift a few batteries again. Once again, I felt no pain when lifting them. This morning, I wake up and my left shoulder feels the same as a week ago, and I have a very slight pain in my right shoulder. I feel a dull pain in the rear part of my shoulder just in front of the point of my shoulder blade as I try to reach my arm out and foreward.
I read Eric Cressey's article "Cracking the Rotator Cuff Conundrum", should I rest my shoulder until it feels better and put Eric's article into practice, or could this be something serious?