Guild Wars 2

I have already reached lvl 80 and my exp bar is already maxed out. The problem is, when I press the H tab and to go Mastery, both Central Tyria (8 points) and Heart of Maguuma (0) is still locked. I understand that Maguuma is 0 because I have not ventured there yet. Also, I am still working on my story quest atm. Is that the reason it is still locked? On the lower left part of my screen – right beside the exp bar, where the hero lvl used to be prior to reaching lvl 80 still states ZERO. Lastly, does account verification also matter here? im still waiting for my account to be verified via purchase of the game + expansion. Thank you.

You need to do the 1st HoT story step to unlock the its content, which includes the mastery system.

is it possible to do the HoT story without finishing main story line?

Yes

noted, thank you!