I am constantly being pushed or blocked by Barbas the dog or Lydia and it's driving me crazy. They are standing/walking way too close. Is there anything that can be done about this?

Unrelenting Force

Kill them

That's why I roll solo, and why I told that damn dog to GTFO.

I'm sure that for those on PC, the modders will fix this sort of issue. For console users.... probably no hope.

If I tell him to stop following me will he just go to the next part of the quest and wait for me?

Nope your follower will just go back to where you keep them/found them.

Never had a problem til I took a DB Initiate along with me and she kept nudging me forward. Lydia behaved in that reagrd at least

Actually I think somebody mentioned a mod like that (at least for the dogs) on here not too long ago... But I'm searching Nexus now and don't see it. What I do see is several mods that make the dogs quiet, which I find pretty funny, since during the quest with Barbas, the noise didn't bother me as much as the shoving (he shoved me right off a cliff once, the stupid mutt).

You know, I thought I remembered a "fix" mod for Barbas - yep! There it is!

http://www.skyrimnexus.com/downloads/file.php?id=2686

My character's companion Erik the Slayer got her killed by getting too close. She stopped outside of Winterhold to allow Erik to catch up, and while waiting went over to the edge of a cliff to admire the panoramic view of the Sea of Ghosts. So Erik comes running up behind her and slams into her from behind and she goes right over the cliff. What a klutz that guy is.