Give it as much time as you need. Injuries can go from minor to major in a matter of even one workout. If it gets worse, then you may have to cut shoulders out altogether. Not trying to scare or anything but I take injuries seriously now...you'd be surprised at how much progress an injury can destroy.
ps. I haven't got that much experience on you, I've only got 2-3 yrs worth. Eric has like a billion compared to us though
