Restrict Viewing of post on both front and backend?

to restrict on the back-end you can use the default author role.

and on the front-end you ca use something like:

function check_rights_8876(){
    global $post,$current_user;
    $author_id=$post->post_author;
    get_currentuserinfo();
    if ( is_user_logged_in() ) {
        if ( current_user_can('manage_options') ){// admin
            return true;
        }
        if ($author_id = $current_user->ID ){// curent post author
            return true;
        }
    }
    return false;
}

Once you have this function defined you can check before displaying the post like this:

if (check_rights_8876()){
    //display the post
}
else{
    //Sorry but you don't have rights to access this post massage here
}

Hope this helps