Okay, now this MIGHT be a bit of a stretch, but hear me out.
The day I got my Wii, several games of Monkey Ball's "Red Light Green Light" and Wii Boxing, as well as some frantic Zelda fishing left my arm and shoulder very very sore for 2-3 days. The Monday after launch, I literally felt like I had been lifting weights all day on Sunday.
Wednesday morning, some of the soreness was still there when I woke up, but about 25 minutes after waking up, I pinched a nerve or a muscle or something in my neck. I couldn't move my head all day long, and I was in excruciating pain for about 6 hours. By that evening, my neck had started to loosen up, and now I'm pretty much back to normal.
BUT, I had to take that day off of work, and as a result, I won't be able to take this Friday, my birthday, off of work. BOO.
Anyways, just saying. If you have sore muscles from the Wii, be careful or you could do what I did. I don't have any real proof that this is how I pinched the nerve/muscle, but I think there's a pretty direct correlation.
Mental note: stretch next time.