When I create pages in Pages library, I get an error saying 'The page name already exists' or 'its checked out for editing by another user'. But when I go to Pages library and try to find that page, it may not be there. It will only be visible from that user's login which is displayed in the error page. Once that user checks-in the page, then everyone can find that page in the Pages library and can start editing it. This happens because there is no checked in version of the page, the user might have created it and left it without checking in. If I go into View All Site Content and it shows 10 documents. When you actually go to the Library All Items view (No filtering), I can only find 2 documents. How to fix this issue?
Normally what happens here is, there are documents in the library that were uploaded for the first time and never checked in. So only the owner of the files can see them no matter the view or permissions you have. Go to the Document Library Settings page of the respective Pages library. Under the Permissions and Management group, there is a link named Manage files which have no checked in version. When you click the link it will show all Checkedout files.