why is my apple id disabled

We are fellow users on these user-to-user forums, we won't know why.

Have you tried its resetting the password : If your Apple ID has been locked - Apple Support ? You might then need to log out and back into your account wherever you're using it : What to do after you change your Apple ID email address or password - Apple Support

If that doesn't fix it then contact iTunes Support : https://www.apple.com/emea/support/itunes/contact.html