why are my files in pages greyed out

If the grayed out files are anything but Word .doc, .docx, .rtf, or .pages documents, then Pages cannot open them from a File chooser.

You can drag/drop compatible image files and PDFs from the Finder onto an open Pages document. Otherwise, you access those grayed out files via the Finder and applications that are designed to open them.

FIles that Pages cannot open as unsupported formats will be gray in the File Chooser and all gray in the File Save panel.