Q: pre ordered music, i bought on my iphone and cant download on computer(or phone).how do i get it in my library?

Hey there russp112!

I have an article with some information for you regarding pre-orders:

Downloading a pre-ordered item

When a pre-order item becomes available, you will receive an email letting you know your pre-order is available for download.

If you've enabled iTunes to automatically download prepurchased content, then your pre-order content may already be downloaded to your library. If not, simply click the download link provided within your email notification, and your pre-order content will begin to download. Alternatively you can use the "Check for Available Downloads" feature in iTunes on your computer by choosing Store > Check for Available Downloads to begin downloading your pre-order.

iTunes Store: About Pre-orders

http://support.apple.com/kb/HT5714

If you are still having issues with the pre-order after reviewing the information in that article, you will want to report an issue with your purchase by following the steps in the article below:

How to report an issue with your iTunes Store, App Store, Mac App Store, or iBooks Store purchase

http://support.apple.com/kb/HT1933

Thanks for coming to the Apple Support Communities!

Regards,

Braden