You can absolutely do stuff like that. Maybe your party were awarded noble titles by the king for service to the crown. Then one day, when they're hanging out at their new keep, a messenger comes by with a court summons because they haven't been paying their taxes. Now they have to investigate the tax law, figure out what they owe, why they didn't know about it, and what they have to do now. And now you can go into a Robin Hood arc, where the players discover that this kingdom's tax system is super messed up, and preys on the poor and uneducated, and you have the added complexity of, your players are lords now, will they want to rock the boat in this kingdom that likes them? They're adventurers, so they can probably afford to just pay the ridiculous taxes, but that would mean leaving every other victim to their fate