Stuck at level 50

[DPZ2]

So ive been grinding a bunch of low exp quests and idk how to start heavenward. Do i have to do EVERY single pre patch quest to start heavenward

You have to do all of the Main Story Quests, identified by the meteor symbol, for the patches 2.1 through 2.55. Side-quests are optional.

The reason the post 2.0 quests have so little XP is that, back in the day, they had no XP assigned, as there was no level above 50. That being said, if you do all of the MSQ you'll have a good start when you hit Heavensward.

On another note, you'll be able to get through them much faster when 5.3 releases on 11 August, as they streamlined the post 2.0 story quests. Doesn't help right now, though.