Someone keeps hacking my apple id...

Every now and again I try and buy or download something and sign in to my apple i.d and it says that the password is incorrect. Each time this happens my security questions say they are also wrong so I have to do an e-mail verification to reset it.

I regularly change my personal e-mail address password so I know no one can get in to my own mail account and I change my apple i.d password to really obscure things and tell no one what it is nor is it the same as any of my other personal passwords.

I'm a bit concerned now as this is happening more and more regularly. I am not using the exchange server and have not set my account to reset the password automatically and no one I know has this happen like this.

Can anyone shed some light as to why this keeps happening and if it could be a technical fault or if it seems like it is someone doing it?

Thanks in advance!