iPod Touch 4th Gen Does Not Sync

Basically had an black iPod 4th generation for 2 years this christmas. It worked perfectly til September last year and the suddenly out of no where it seemed to stop syncing. I click the sync button and it seems to either do nothing and the sync button becomes unable to click again or it starts to sync and then just stops. My iPod is also does not back up, or sync ANYTHING. Im finding this really stressful as i can't use my iPod to the full ability. Ive done updates with my iPod and my iTunes, everything is up to date and i have also tried many other iPods which worked fine with my iTunes, i did this to make sure it was my iPod which was the problem. Some one please help my dodgy iPod!!!