Allow users to see own content only
"Allow users to see own content only", You can achieve this using contextual filter and relationships in advance settings in views module, Given by you already set the contextual filter set filter to login user, 

1.) In Advanced settings add field Content:author in relationships. 

2.) Then in Contextual Filters add User: Uid and choose provide default value and set Provide default value Type User ID from logged in user.