Hello Chawit,
Thank you for contacting iTunes Store Support to let me know you need some assistance. I have just finished reading your request, and its to my understanding that you have forgotten your Recovery Key and would like to be issued a new one. I can certainly see the need to have this looked into. My name is Melissa and it would be my pleasure to assist you today.
Chawit,I have looked into this matter for you, and I have found that you can generate a new one if you know your password and have access to at least one of the trusted devices associated with your Apple ID. After you activate your new Recovery Key, the old key will be deactivated. You won't be able to use the old key to reset your password or access your account.