This may be a bit flakey as i’m typing on a phone, but perhaps something like the following:
$query_store_args = array(
'post_type' => 'posts',
'cat' => 'store',
'posts_per_page' => -1
);
$query_store = new WP_Query($query_store_args);
if( $query_store->have_posts() ) :
while( $query_store->have_posts() ) : $query_store->the_post();
// code I added above
endwhile;
endif;
Edit: forgot a line