To isolate where the problem is coming from, try using a different set of headphones with the iPod. And try using your iPod headphones with a different machine. If the problem persists when you're using different headphones with your iPod, you may have a problem with the headphone socket on the iPod. If you're luckier, it's an issue with the wiring of the headphones themselves. Are there any visible kinks or creases in the headphone wiring or a bend or dent in the mini plug itself?

i cant hear nuthing i put the headphone n another machine it work but when i put them in my ipod it dont work at all

Yep, same problem here. I think it's gotten worse. First if you plugged in the headphones just so, it sounded okay, but otherwise the vocals were muted way down. It's just gotten worse from there. Now I can only hear a very small portion of the frequencies I should.

Basically I can only listen to pianos now.

I'm guessing something's wrong with the leads. But can I just open this thing up and tinker with it?