guitar problem

[DemonKill12]

ok so when I'm playing. or even at the main menu sometimes when I press up to hit the key or go up in the menu it doesnt work.. it like freezes and it goes all the way down and I have to force it to work. then I shake the guitar a bit and a forceit around and 5 mins later it works again? whats going on? am I doing something wrong or is it broken? or what?