Previous/Next Single Pages

Define “normal post” (?)
There is this template tag:
http://codex.wordpress.org/Template_Tags/posts_nav_link
used in multiple posts views (like index, archives, category etc.)

And there is the http://codex.wordpress.org/Template_Tags/next_post_link and its pair http://codex.wordpress.org/Template_Tags/previous_post_link used on single post view – which means they should be included in the single.php template file.

Pages cannot have any next/prev links since they are not part of the chronological stream of the posts.