variation-stock-shortcode.php

<?php

// Shortcode to get variation stock. usage example: Current Stock: [variation_stock id="2525"]
// The id being entered should be that of the variation, not the product. 

add_shortcode('variation_stock', 'variation_stock');
function variation_stock( $atts ) {
  if ( ! $atts['id'] ) {
    return '';
  }
    $varid = $atts['id'];
 	$varobj = new WC_Product_variation($varid);    
    $stock = $varobj->get_stock_quantity();
  return (int)$stock; // prints 19, ie the quantity of variation 2525
}