Very confusing Ipod classic glitch

So a problem i've had recently is this one on my ipod touch where it skips songs and won't play them, and sometimes whole albums!

I'll explain the variables:

 

So I used to be able to listen to any song I wanted, just fine up until just recently..

I used to listen to the band Behemoth a lot (no surprise) and when I went to play them about a month ago the whole album would just skip to the next song until it got through the whole album, playing nothing. This is the same with a few of their albums, but not all, some of theirs play, and they certainly all used to.

Now this did happen after i synced my Ipod by adding some new music which made me think "hmm, maybe it's a bad sector on the HDD, but it can't be because when I re synced recently with a whole bunch more bands including band of whom begin with B or A which would push Behemoth down the line my HDD Behemoth still wouldn't play!

 

Another thing to note is this one time I went to play a song off of Chelsea Grin's EP and A couple of the songs wouldn't go but the rest would, but then when i went to show my friends what went wrong they all played fine and have ever since.

 

The second song off of my favourite Drudkh album also doesn't go :(

 

Any ideas on this very weird issue?

can you run check disk when it is plugged in?