I solved the problem by opening the pages panel and dragging pages around until they were all aligned the same. It took quiet some time page by page but it eventually got everything looking symmetrical again.
I wasn’t able to upload a screen view.

Thanks for everyone’s assistance.

I have about 60 pages and the last 20 are off-set to the left. If you place the cards in 30 pairs down a table all lined up then suddenly move the next pair towards the right about half a page and continue lining them up in pairs down to the bottom is about what I see in the pages window and also in the main window. The white pasteboard behind the page is also misaligned in the same direction. It hasn’t always been like this. I started this document a year ago and applied several masters to it and saved several versions of the same file.