iPod classic won't play music through both headphones

I thought it was the headphones, but it's not. I used my trusty headphones yesterday and the music wasn't coming through the right ear of the headphone - if I tried moving the jack around it might stutter into play. Sometimes if I took the jack out slightly it might then play for both ears, but of course I can't be holding the lead all day! I've tested several headphones and I'm certain it's a fault with the iPod. Have tried switching off and on, tried blowing away any debris inside the headphones port - nothing.

Can anyone help me please? Help me Obi-Wan, you're my only hope.