How do I display the function the_content in this loop?

by

try this instead:

...

global $post;
while ($q_query->have_posts()){
  $q_query->the_post();

  $loophtml .= "<li><span class="list-question-title">" . "<a class="list-answer-link" href="" . get_permalink() ."">" . get_the_title() . "</a></span>";
  $loophtml .= get_the_content();
  $loophtml .= "<span class="list-number-answers">" . get_comments_number() . " comentarios</span>&nbsp;&#183;&nbsp<a href="" . get_permalink() ."">Comentar</a>";
  $loophtml .= "</li>";
}
wp_reset_query();

...