Shoulder pain from karate- is this something I need to worry about?!

Shoulder pain from karate- is this something I need to worry about?

I started karate lessons about a week ago and for the last two days I've been taking hour-long classes. When I woke up this morning, I had pain in my right shoulder which is the one that I do most punches with. It's odd, because I didn't have any pain during my class. It's not that severe-it just hurts to rotate it. Is it possible I pulled a muscle? How long do these sorts of things take to heal? And what should I do to help it heal faster?
Thanks in advance!

i tore my rotator cuffs at work, (both shoulders, one at a time) does the pain get so bad at times that you cant even move your arm? if so, then you should go get it checked out. but if it is only after you have rested it like after sleeping, then it probably isnt anything to worry about. just sore muscles. some sports cream, or ice should help.