Is there a way I can do a search, without typing "Objective C" each time, and make it my default area? I don't care about C, C++, Android, PHP, etc. (at this point in my life).
Sure, bookmark the URL, here is one that should do what you want:
[objc] into the search box. objc is a synonym for objective-c, and the bare tag search will take you to https://stackoverflow.com/questions/tagged/objective-c, sort of the "home page" for questions tagged objective-c.
If you have a facility allowing some kind of custom search shortcut to be defined (my browser, OmniWeb, has this built-in), you can make e.g.,
so $arg perform a Stack Overflow search. Then
so [objc] will take you to that page.