Im trying to burn a cd from the playlist on my itouch but it wont work so I tried to add all the songs into a playlist on itunes but not all of the songs on my itouch are on the computer how do i get them on there...btw all of the songs i bought on itunes

Hello DrPerry07,

Thank you for using Apple Support Communities.

For more information, take a look at:

Downloading past purchases from the iTunes Store, App Store, and iBooks Store

http://support.apple.com/kb/ht2519

Using iTunes 11 or later

1. Open iTunes. (You can download the latest version of iTunes.)
2. If you're not already signed in, choose Store > Sign In and type your Apple ID and password.
3. If you're in the iTunes Store, click the Library button, in the upper-right corner, to go to your library.
   
4. Make sure that you have "Show iTunes in the Cloud Purchases" enabled in your iTunes preferences by going to iTunes > Preferences in the Store tab and clicking OK.
   
5. In your iTunes library, click the content type you wish to download using the content selector in the upper-left. Choose Music to download music, Movies to download movies, and so on.
6. Locate the item or title you wish to download.
7. Click the download icon to download that item.

iTunes Store: Transferring purchases from your iOS device or iPod to a computer

http://support.apple.com/kb/ht1848

To transfer iTunes Store purchases from your device to a computer, follow these steps:

1. Connect your device to the computer. If it is synced with another iTunes library, the following dialog may appear:
2. Click the Transfer Purchases button.

Have a nice day,

Mario