single.php

<?php
  $post_id = 500
  $p = get_post($post_id);
  $args = array(
    'date_query' => array(
      'before' => $p->post_date,
//      'after' => $p->post_date
      'inclusive' => true,
    ),
    'exclude'=>$post_id
  );
  $posts = get_posts($args);
  print_r($posts);
?>