I had the annual flu shot just last week and it took my arm four full days to recover. That same reaction was standard for the rest of the folks getting the shot the same day. We thought we were all goofy, but now that you have mentioned it, it isn't such an isolated problem. Maybe it is a strain that our bodies just don't like.

I had such discomfort that I said that I would not get the shot next year. Chicken, I guess. My arm was really, really sore. I had a hard time getting to sleep for three nights!