Hey guys I just have a quick question about beginning Dragonborn's main quest? Do you have to find out that you are Dragonborn to do the main quest in the DLC? I would really like to do the DLC without having to be known as Dragonborn because I don't want to do the MQ.

You have to play the main quest up until after you've visited High Hrothgar as far as I know. This means triggering Dragon spawns also. This is at least the requirement to do Dragonborns main quest.

You can still visit Solstheim and do side/misc quests prior to this.