Problem : Page navigation problem with custom query ?

Solution :  Find below

wp_Pagenavi    in query posts:

  1.         Download the Pagenavi plugin from the wordpress
  2.         Install plugin & active plugin
  3.         finally  use the below code     
<?php query_posts('showposts=6'.'&paged='.get_query_var('paged') ;?>
<?php while ( have_posts() ) : the_post(); ?>
<?php the_content();?>
<?php endwhile; // end of the loop. ?>
<?php wp_pagenavi() //call pagenavi?>