Only current ones or ones you haven't started will be on the map. But if we can figure out which was the last Main Scenario quest you already finished, we can point you to where the next one should be.

If you go to your Quest Journal, there are two buttons at the top of the left-hand panel, "Current" and "Complete". When on "Complete" it should look something like this:



Just below the "Current" and "Complete" tab buttons is a drop-down for filtering different kinds of quests. Make sure that's set to "▸ Main Scenario Quests" like it is in the image. Then below that it should list all of the MSQs you've already finished. What's the last one listed there? (You may need to scroll down to get to the bottom of the list.)