ITunes won't let me check/uncheck songs?

I used to be able to check songs I want on my iPhone but now iTunes is not giving me that option. The current version of Itunes doesn't do that. When I plug in my device, it only allows to sync all songs or check artists, genres, or albums, but the option to check individual songs in the summary page is unclickable (not available).

I stopped using iTunes for many reasons.many many reasons.

Same difficulty.

  • Why won't my iTunes let me sync my songs? I have restarted my laptop, un-installed iTunes then reinstalled it again several times. And after I do any of them I will plug my iPhone 4S into the USB (with cable) port and it'll start syncing my music but then a notification will pop up and say my music can't be found. But all my music is still in the iTunes. I don't get it?
  • Why won't iTunes let my iPhone go into iTunes? My brother put a password on my iPhone, and he forgot it. I, stupidly, tried a whole bunch of passwords to see if I could get it, and not my phone is disabled. I tried connecting it to iTunes to get it undisabled so I can restore my phone, but it keeps saying I need to put in the password in order for me do get onto iTunes. This happen to anybody else? Can somebody Please help me!
  • Why won't iTunes let me put songs on my iPhone? So I downloaded Eminem's new album from iTunes, and whenever I try to drag the album from my library to my phone, it comes up with a red circles with a line through it where my cursor is, why? I know I have enough space on my iPhone, but I haven't updated it to iOS 6.1.3 yet (I have a 3GS, cause I'm cheap like that) so is that the problem?
  • Why won't iTunes let me put certain songs onto my iPhone? ITunes used to work fine until recently. Now there are certain songs or artists that won't drag and drop onto my iPhone. Any answers?