Text box is always justified.

When you talk about Text Frame Options, I'm assuming you are referring to VERTICAL justification inside that box?

If so, you've changed the default. In your current document, without selecting any text box, open up Text Frame Options and make sure it's set correctly, because anything you set there now becomes the default for any new text boxes you draw. This changes it back for this one document....however, if it's happening for ALL new documents, then you have inadvertantly changed InDesign's deafult, in which case, change the Text Frame Options with NO document open.

If you are using additional Object Styles in any way, make sure you haven't created and selected one that is giving you justified text.

Since this is an issue within the interface I would suggest trashing your InDesign cache files. This is not the same as trashing preferences.

To do so:

For Macintosh Users: The User Library folder in which InDesign’s cache files are stored is hidden by default on most Macintoshes. To access it make sure that InDesign is closed and click on the desktop to launch a Finder Window (Command-N). With this window in column view follow the path User>Home folder (it’s the folder with an icon that looks like a house—it may have the user’s name rather than “Home”) and click on the Home folder. With the Option Key pressed choose Library from the Finder Go Menu. “Library” will now appear within the Home folder. Within the Library folder find the “Caches” folder. Within the Caches folder find and delete the entire folder “Adobe InDesign”. I find that deleting the InDesign cache folder completely leads to a lasting change.

For Windows Users: On Windows 7 and above the caches files are hidden. To find them go to the Control Panel and open Folder Options and then click the View tab. Then select “Show hidden files and folders” or “Show hidden files, folders or drive options” in Advanced Settings. Then delete (or rename) the folder at the end of this path: C:\Users\[User Name]\AppData\Local\Adobe\InDesign\Version [#]\<Language>\Cache.