This is a solution for anyone who has found this really annoying glitch during the companions questline.
I had just cleared out Shimmermist Cave and had to go back and report to Farkas in Jorrvaskr house. When i walked in the front door Farkas drew his sword and started talking to me. I followed through with the conversation and closed the convo sequence, walked about 2 steps and he started talking again, stopping me in my tracks! i couldnt carry on with the game at all because he kept stopping me!
I reloaded my save just before entering the house and tried again, it happened the same! so i checked on some forums and found this solution, which i am now sharing with you! but i cannot credit anyone because i cannot remember where i saw it!
If you check your STATS tab in the pause menu and then go down to the CRIME section, see where you have any bounty! you have to pay off ALL bounty in every city you owe bounty. i didnt realise i had 1000 gold bounty in winterhold, so i went to winterhold and paid the guards. when i went back to Jorrvaskr house and opened the door, Farkas didnt jump on me straight away!!!
I could now carry on and speak to the next guy he aimed me towards!
This happens because Farkas and his brother Vilkas are part of the city guard team, so they treat you like a criminal but dont have the "go to jail or pay the fine" conversation choices!
Hope this helps everyone that gets stuck with this!