Paragraph justification just stopped working at all

[defaults7dbsejfatu0]

Help please!
I'm quite new to InDesign. using the latest version.
I have a document with a few different paragraph styles, all simply individually set up, no parents or children, no character styles. Many were are full justified, some are left justified. It was working fine, everything looked great.

Then, one day, I was importing some text into new text boxes, i'm not exactly sure when, but now justification does not work at all. All text is left justified on the pages. The paragraph styles are the same as before, stating full justification but its just not appearing on the page. Toggling the justification between left, right, full, does nothing to the text on the page.
I have searched for character overides, parent-child issues, I have created new text boxes, re-started everything, nothing works. Its a huge document and I do not want to re-build it. Will probably attempt a backup and complete re-install.
Has anyone seen this before? Please help!

[Scott Falkner]

Hard to know what's happening without having something to look at. Can you provide a screen show showing frame edges and invisible characters?

[Eugene Tyson]

I agree with @Scott Falkner 

You could try 
If a document is not behaving well then try 

File>Export 

Choose IDML

Open the IDML in InDesign
Save the file as a new InDesign file with a new name
See if the issue persists.

[Willi Adelberger]

1. Did you select the text?
2. Are the text franes locked?
3. Did you import a style which overwrote an existing style with a different definition?
4. How do you start new lines in a paragraph? With return or automatically?
5. InDesign has 4 different justifies, which did you use?
6. Show us a screen shoot with invisible characters turned on.