after using itunes, i can not open my cd drive

There is no correlation between iTunes (software) and your optical drive (hardware).

If the physical eject button on the drive doesn't open the tray, reboot and try again.

Check in Device Manager to see if it is enabled.

As well as the tip Skcusime has provided, try the eject CD button in iTunes:

and then...

There is also a setting that will cause the CD to automatically eject after it has been imported. It's in Edit / Preferences / General / When you insert a CD: Import CD and Eject: