I honestly don't know. I've just been playing and enjoying. Is the main quest the Dragon Burial Grounds? Or joining the Stormcloaks/Companions/etc.? I haven't done that yet. Just playing and building my fortune so I can retire with Hroki.

the MQ is about the Dragons it continues after you get your first shout and you go to visit the greybeards its that line.

personally im ignoring it.

Gotcha. I've been killing dragons so I guess I'm on my way.