Page title in post query

Your original code has a typo – the ampersand is used to separate arguments, so it should be:

'posts_per_page=10&category_name=" . $post->post_title

However, since this is a new query in addition to the default, a new instance of WP_Query should be used instead of query_posts:

$args = array(
    "posts_per_page' => 10,
    'category_name' => $post->post_title
);

$related = new WP_Query( $args );

if( $related->have_posts() ):
    while( $related->have_posts() ):
        $related->the_post();
    endwhile;
endif;