When i leveled up to 60 ( i'm life) i got 3 icons on rightside of screen, one leading to the forest lord, one to the tower of the helephant, the third i have now forgotten, theres no question marks shown on the maps, i have been given no reminders, so now i'm questless at level 68.
have this happened to someone else, perhaps afk for a few seconds, when these icons are shown.
Most of the quest bubbles that show up on the side of your screen are not exactly required quests, they are reminders of ones you could do or messages from your teacher that a new spell is ready for you.
At level 60 you get quite a few, one can be for WaterWorks, Helephant tower you mentioned, Merle sometimes says he needs you but does not, the guy standing in the Celestia Camp Base may want you to make his tea set things like that.
I have had friends several times become questless - mainly in DragonSprye though. What we do is back track into the area they were last at and look for someone that they may of by accident Declined a quest from instead of Accepted. Sometimes even taking on a Side Quest gets them back into the loop of leading them back to the main story line.
Sometimes for no random reason the bubbles pop up. Like on my level 30 wizard I got a bubble saying " I'm simeon come see me etc".... When I already did. It's just a glitch. If it looks familiar and you think you already did it you probably did. The glitch usually happens every time you level up or when you haven't played a certain character for quite a while.