Add Pagination for Blog/Post list at custom Page

Download the following plugin : http://wordpress.org/plugins/wp-pagenavi/
Add Following code in your current shortcode function :

function sc_newsletter_list($atts) {
     extract(shortcode_atts(array('limit' => '10', 'number' => '3','fullpage' => 'no', 'category' => '', 'title' => '',), $atts)); 
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
    $number = $limit;
    $wp_query = new WP_Query(
    array(
    'post_type' => array('Newsletter'),
    'paged' => $paged,
    'posts_per_page' => $number,
    ));

    $output = '';
    $counter = 0;
    if ( $wp_query->have_posts() ):      
    while( $wp_query->have_posts() ) : $wp_query->the_post();
   ...............................
   .................................
// Pagination : [wp-pagenavi] plugin used
    if(function_exists('wp_pagenavi')) { 
      $output .= '
'.wp_pagenavi( array(
                    'query' =>$wp_query   
                )).'
'; 
            }