title: Function working with an existing hook, doesn't work using it a custom do_action hook
body: <p>I know that add_action is used to call a function at the location of a hook. I used add_action like below and it gives me the output I need (Which is the price of a product in WooCommerce): </p>
  
  <pre><code>add_action( 'woocommerce_before_variations_form', 'woocommerce_single_variation', 10 );
  </code></pre>
  
  <p>I used the above code inside a custom plugin that i built.</p>
  
  <p>But now I want the price to appear in a different location. I read about do_action and I learned that it is used to make new hooks. </p>
  
  <p>So I made a new hook like below - </p>
  
  <pre><code>do_action('unique_mycustom_hook');
  </code></pre>
  
  <p>The new hook is kept inside "content-single-product.php" inside Woocommerce template folder. </p>
  
  <p>And then I called my function at my new hook using the code below inside my plugin file. </p>
  
  <pre><code>add_action( 'unique_mycustom_hook', 'woocommerce_single_variation', 10 );
  </code></pre>
  
  <p>But this time I am NOT getting any output!</p>
  
  <p>Do you have any idea why add_action worked in the pre-existing woocommerce hook but did not work in my new hook made using do_action? </p>
  
  <p>Thanks.</p>
  
  <hr>
  
  <p><strong>UPDATE - 
  I am adding more information on request.</strong> </p>
  
  <p>The purpose of my hook in woocommerce is to have the price of the product appear in a fixed sidebar. So I made a <code>&lt;div&gt;</code> section inside the file <code>"content-single-product.php"</code> inside WooCommerce template folder. This is the exact code that I added to the woocommerce template. </p>
  
  <pre><code>&lt;div class="this_sidebar_is_fixed"&gt;
     &lt;?php
        do_action('unique_mycustom_hook');
     ?&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>Then I am calling the hook using a custom plugin I have. </p>
  
  <p>Still it is not working.</p>