The optical drive won't read or eject once I put a disc in.

My own MacBook is doing something similar; it will eject but not read. Until I get around to fixing it, I'm using an external optical drive.

If you have an external drive you can boot to, see if you have the same problem running off the other system. If you don't have an external drive, but have access to another Mac with Firewire, and if your Mac has Firewire (you don't say which model you have), you can boot up your Mac in Target mode (hold down T while booting; you'll get an orange Firewire icon bouncing around the screen), turn off the second Mac, connect the two with a Firewire cable, and boot the other Mac while holding down the Option key to get into the Boot Manager, where you can choose to boot to your own Mac's system. Of course your system must be one that will boot the second Mac. At this point, you can try the optical drive in your Mac and see if it works. If not, I'd say the drive is toast.

If you've still got warranty left, you should call Apple immediately to at least get the defect on record, and make arrangements to send it in for repair or take it to an Apple Store. If you have no warranty left, then ifixit has replacement drives and instructions. If you don't want to fix it yourself, a good service is iresq.com.