Here is a solution(only if you have knowledge in php):
1.Open /wp-includes/comment-template.php
2.Find the “function comments_template( $file = ‘/comments.php’ ){“
3.Inside the function you will see :
if ( ! (is_single() || is_page() || $withcomments) )
return;
Change this to
if ( ! (is_single() || is_page() || $withcomments) )
//return;
4.Open /wp-content/themes/yourtheme/index.php
add “<?php comments_template(); ?>” inside post loop
“while (have_posts()) : the_post(); “
Please note that the post comment text box will be displayed along with comments.