I've had have this problem multiple times. I can't seem to find the main quest line. I just finished promoting Dead Mike to Undead Revevant. After finishing a side quest I thought the Quest Finder was suppose to direct you back to the main story line. But in this case it isn't doing such a thing. It keeps bringing me back to this side quest that I don't want to do. I then tried looking for the main quest again and tried to remember what it was. I somewhat guessed the main story line and am hoping that it's the main one.
But please Kingsisle fix this. It's annoying and is a big headache to look through all my quest pages to find one. I have 15 quest pages and I find it a hassle and annoyance. This isn't the first time it happened to me.