I have an american strat and literally within the last 30 minutes it has aquired a huge buzz. Especially when I play the 12 harmonics, Its not a string buzz its almost like something inside is buzzing. When i push the neck down it is much better! But when I release the tension it once again buzzes. I've now realized that when i play a harmonic (natural) on the B string it produces almost a wah like sound.??? Has this happened to anyone else, what should I do, what is it?

Thanks UG (p.s I know this should be in the other forum but no1 will answer it there and I need some help, I'm scared!!!)