Custom post type pagination

Hi !
I am Developed the custom post type wp plugin but I can’t added pagination how to added the pagination here my script .Please let me know how to solve this

<h1 class=”post-title”>   Portfolio</h1>

<?php query_posts (array(‘post_type’=>’Portfolio’,’posts_per_page’ => 4)); ?>
<?php $mypost = array( ‘post_type’ => ‘Portfolio’, ‘posts_per_page’ => 4 ); $loop = new WP_Query( $mypost ); ?>
<?php while ( $loop->have_posts() ) : $loop->the_post(); {?>

<div style=”width:960px; min-height:340px; border:2px #909090 solid; padding:5px; margin-bottom:20px;”>
<div class=”portfoliotitle”><?php the_title(); ?> </div>

<div class=”portfoliodes”> <?php the_content(); ?></div>

</div>

<?php } endwhile; ?>
<?php wp_reset_query(); ?>