Is there a way to show hidden locations on the map. Is there an easy way to idenify them on the local map. I stumbled on one early on but i would have missed it very easily

In previous Fallout games they had an Explorer perk which did just that --- showed ALL locations on the map, even if you had never been there. You could not fast travel to the locations until you actually found them "in person" of course, but it still let you know what you missed. When I was hitting max level in those games, I would sometimes pick up Explorer.

No such perk currently exists in Fallout 4 (unless someone mods it in, if that is even possible).