"Get letteralmente in inglese significa ottenere"... no, this is not true.
Gabriele, the word "get" is not a simple word, and you need to learn it and practise it to understand it fully. It's a very, very useful and flexible word.
Your examples of "get at home", "get at school" and "get believe" do not exist in English. ("Said me" is also wrong.)
As for the X-rays, the doctors do the X-ray and you get an X-ray.