Hi I've had my bike a month now and just noticed the chain rubbing together when I'm in the small,chainring and the small cassette cog.
I have the x0 type 2 mech on a 2x10. Has the bike shop got the wrong chain length or is the clutch mech bust?
Put it in the other extreme, the big-big, and see what it looks like then. It may be a case of sizing the chain to suit one extreme vs another. If your bike is a dually then you also need to account for the suspension lengthening the rear end under compression.
Rimmer - "There's an old human saying - if you talk garbage, expect pain"