My deltoid hurts a little

I just got my flu shot for the year. The needle was pretty thin so I hardly felt it, but now my shoulder is starting to feel sore. The administering nurse Kathy asked me if I had any food allergies. I almost told her raisins. She said to be sure to get a good nights sleep. New studies showed that the effectiveness of the vaccine is diminished by 50% if you sleep for only 4 hours afterwards. 50%!? That's a pretty dramatic performance drop. I'll try to get to bed earlier tonight. Just as soon as Conan O'Brien is over.