How to get current pages menu text?

You can get a Menu’s entire item list with wp_get_nav_menu_items(). Then, loop through them all and test against the current post_id, and voila, you have all your data.

<?php
$menu_items = wp_get_nav_menu_items( 'main-menu' );
foreach( $menu_items as $item ) {
    print_r( $item ) ; // see what you can work with
    // carry on
}