Jon–
It sounds like a running position/technique issue.
Check your stance and start position.
Are you over extended?
Pro Episode #16 – The Dreaded Low Back Pump Out

Pro Episode # 45 – Pro user Request Friday: The Dread Piriformis Syndrome (Like the Dread Pirate
Roberts…but Different)
Episode 49: Running in Overextension with Fixes and The Machine

What is your foot strike when you run?
Episode 305: Solving Problems With The Tunnel: The Foot Strike

Going to a more minimalist shoe asks more out of your posterior chain and your ankle rom.
If there was a big difference in your prior shoe and the new one purchased this could be an impacting factor.