Show users last read posts for each user?

You should use update_post_meta with post_readed_by meta key when a user visit each single post.

you can use the_content filter to update this with checking the is_singular()

Hope you know how to sort these

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)