Metadata missing from iPhoto

I've just been forced to change from iPhoto to the Photo app and can I say I'm less than impressed. It is so much more difficult to navigate to start with. Half my photos have come across without their metadata such as titles. I spent hours sorting my photo library and naming photos and now I have photos that are missing everything. Is there any way to get it back? Why did this happen to some and not all? Very disappointed that the transfer wasn't seamless. Now I suppose I'll be spending hours again trying to relabel everything. Any solutions?