why are my comments rotated 90 degrees when i import them from another document

That has to do with the original page rotation vs. the new page rotation. Just because both pages look the same does not necessarily mean that there were created using the same page rotation,. Some software thinks it's easier to create e.g. a landscape oriented page in portrait mode, and then set the page rotation information to always display or print the page with a rotation of 90 degrees, so that it appears as a landscape page. When you now copy an annotation from a document that has a page rotation of 90 degrees to a page with a page rotation of 0 degrees, you end up with a rotated annotation.