Spoiler
After the quest to kill the witches, and you return to find Jorrvaskr attacked by the Silver Hand is where my problem is. The guy came up to me and spoke to me, said something about getting revenge (implying the next quest) but I didn't recieve any new quests or objectives. Talking to any of the Companions yields nothing, as they have no new dialogue options. I can't get further in the questline because of this.
So, can anyone help me out?