I had commented the PREVIOUS flu season (aka not 2011-12, but 2010-11) b/c I had the same thing happen to me. So, this year I was 'smart' and got the flu shot (ok, not so smart) in my non-dominant, left arm. I made sure that I did not get it too high up, etc. Guess what. SAME THING. The only difference is that I could lift my left arm up by only wincing, not outright, holy crap, I can't lift my arm, pain. I got the shot in October and the pain was finally gone by April, so about 5-6 months. There is something in those flu shots that is just not right-- But meanwhile, my husband had the shots at the exact same time as me both years and had no adverse reactions at all. I just don't get it.