Songs not synching from PC to iPhone 5 (also wrong album artwork)?

At first I was having trouble with incorrect album covers being applied to albums on my iphone, and saw online that I should re-synch. That didn't fix it, so I removed the affected songs (there were about 6 or so, the others were fine) from the iphone, and then tried to re-synch again so that the songs would be put back on from my computer. Now the songs aren't going back onto my iphone at all, even though they're still on my computer. Unplugged, re-plugged, re-synched, still nothing. Can anyone please help?

Hmm… Maybe a connection problem? Either disconnect your music service from your phone then reconnect the account and sync, or try standing close to your internet device or a good internet source if you're going to sync.