I started to listening and reading the PR whole mind sistem..

the question is: i've finished 3rd tape, and understod so far, but if anyone can tell me by details how is he doing PR..
when i try to concentrate my head starts to hurt, and my eyes fells diferent..
is that usual, or unusual..

does it really work that much, that i can PR the William Shakespeare (hamlet) and understand everything??
i'm a begginer in PR so i don't know much..