I'm trying to understand how quests and amity works in this game (I get how they work but read my post and you'll see my confusion). When I was with Jemkas he had a quest listed with a 30 Amity perquisite and even though I have 70 amity with him, it's still locked. Someone showed me the BDO codex page for that quest and it's actually a chain of quests starting with Cruhorn. So I went to cruhorn but the starting quest "To The Quarry" isn't listed under his quests. Am I missing something here ?

Hit the "O" (oh) key and make sure you can see all the quests are visible.  At the bottom of the window is a group of symbols.  Click "All" (the one farthest left) if they are grey and not yellow.

But, it could be a quest chain that PA cut out from all their rehashing of the Serendia quests and their butchering of the Calpheon quests, and it might not exist anymore.