If I had to guess you’ve been Horde before on the warrior and faction changed multiple times there, which can have an effect on the quests resetting but some of the phasing not, so you end up with ! markers you can’t pick up and ? marks you can’t hand in.
Get in touch with the Support team and let them know all the quests you are having trouble with, which zones and NPCs (put as much detail in the ticket as you can), they’ll be able to take a look and try help out