Here’s a quick tip. By default most WordPress themes have a single post page navigation setup so that you are shown a double arrow + “Previous/Next Post Title”.
It also shows you how to customize the text of the link by changing the default
<!--?php previous_post_link(); ?-->
<!--?php previous_post_link('%link', 'Previous in category', TRUE); ?-->
where the link contains custom text and even remains in the same category of the current single post. Now putting it all together if you wanted to maintain the same default post navigation (where the link contains the title of the next/previous post) while also remaining in the same category you can do something like this:
<!--?php previous_post_link('%link', '%title', TRUE); ?-->
For PageLines users you can edit your default navigation by creating a file in your PlatformBase theme called template.postnav.php and pasting the below code in it so that your post-navigation remains category dependent. Of course by editing in the child theme you won’t have this small change overwritten when it comes time to update your core files.
<div class="post-nav fix"></div>