function show_product_pages() {

global $post;
$child_pages_query_args = array(
    'post_type'   => 'page',
    'post_parent' => $post->ID,

);
$child_pages = new WP_Query( $child_pages_query_args );

if ( $child_pages->have_posts() ) :
?>
<div class="columns product-archives">
<?php
while ( $child_pages->have_posts() ) : $child_pages->the_post();
    ?>
        <div class="col col-md-4">
            <a href="<?php the_permalink(); ?>">
                <div class="product_thumb"><?php the_post_thumbnail(array(240, 240)); ?></div>
                <h3 class="product_title"><?php the_title(); ?></h3>
            </a>
            <div class="product-desc"><?php the_content($post->ID); ?></div>
            <a class="cta-link" href="<?php the_permalink(); ?>">Learn More </a>
        </div>
<?php endwhile; ?>
</div>
<?php endif;
wp_reset_postdata();
}
add_shortcode('show_product_pages', 'show_product_pages');