If you can lift your heel up a lot that can be an indication of too much room over the instep. I'd take the boots back and talk to the bootfitters at Inkline and explain your problem to them, see if they can do anything for you.
Also I found developing my calf and leg muscles helped a lot in decreasing shin problems. Get in the gym and develop those leg muscles, you'll feel less pain and be less prone to injury. The other thing that greatly helped me with shin pain was a foam exercise roller.
One of these things:
I just rolled on my shins everyday for a couple minutes. Hurt so bad when I first started but now it doesn't hurt at all and it definitely helped to desensitize my shins.