/**
 * Add a 'back to shop' button on product page
 */

add_action('woocommerce_single_product_summary', 'cc_back_to_shop_button', 35);

function cc_back_to_shop_button() { ?>
  <a class="button wc-backward" href="<?php echo get_permalink(wc_get_page_id('shop')); ?>"><?php _e('Back to shop', 'woocommerce') ?></a>
  <?php
}