I think you need to get to a certain level to do the rest of the main story of Grizzleheim. If you do have to reach a certain level, then do the main story.
If it isn't, try the side quests, or just look it up on a W101 wiki or a web browser.
I have finished the main part of grizzleheim, but it won't let me continue the non main quests.
Is there a certain level you have to be to continue with the side quests?
Austin ShadowBlood Level 25
Grizzleheim comes to us in stages. KingsIsle has shifted the levels we can enter a little bit since it was first released in 2009, so sometimes I don't quite recall the exact levels on a couple of the areas. In general, though, it breaks down like this:
After you complete Ravenscar, you can launch directly into Wintertusk. However, it's strongly advised you wait until after you reach level 48 and get your Scarecrow spell.