Hi,
If this wasn’t a tame, handfed bird when you got him, you may not be able to tame him. He’s not happy, which is why he is screaming all of the time. They vocalize to contact their mate or express when they are scared or not happy. I can give you the links to our behavior and training pages to help you better understand him. It’s typically a very slow process to gain a bird’s trust. After this much time, it sounds like you are making some mistakes that cause him not to trust you. You need to understand his behavior and how to work with a bird that doesn’t trust you.
Pet Bird and Parrot Behavior
Teaching Your Bird
Thank you for asking Lafeber,
Brenda