[MikeD]

Tap on the back of the neck rather firmly... do you hear a buzz in the neck when you do this? If so, it's the truss rod. But, it may not be busted at all. It may just be too loose and not tight in there. If that is the case, just snug it up enough so you feel a little tension on it and the buzz should go away. I have that happen from time to time, especially when a guitar is too humid or too dry, and if your room is 55% (taking into account that most hydrometers are not very accurate and it may indeed be MUCH more humid in there) it may be a bit too moist and causing you some issues. If that is not the problem, then bring it to a competent repair person or luthier to check it out.