Removing Extra Caption tag around image on post of WordPress

To make sure the shortcode executes, save the content to a variable, then run do_shortcode on the saved variable.

<div class="thecontent" itemprop="articleBody">
    <?php $content = get_the_content();
    echo do_shortcode($content); ?>
</div>

The difference is, echoing just literally echoes whatever has been grabbed. PHP’s built-in functions don’t have any special way to process shortcodes so they just output as they’ve been told. By using a WP-specific function, WordPress parses whatever the content is and displays it. This works even if you have no shortcodes in the content.