Full Tilt Help- Shin bang. Why am I getting it? How can I prevent it? +k

So this is my first year using full tilts.  I went to a bootfitter and they fitted my foot with fulltilts so the boots are good for my feet.  I have the classics and have been using #6 tongues in them for park and was getting really bad shinbang.  I then bought a #2 to help.  I read somewhere that you get shinbang because there is space between your boot and the tongue of the boot.  Yesterday i tightened the boots alot so that they would be tight against my shin and there wouldnt be this space.  This made it even worse!  The #2 seemed to not flex at all and i just got really bad shinbang.  Today i made the #2 tongues super loose with alot of space and the shinbang wasnt that bad.  But my skis felt unstable when skiing switch and the light powder that my mountain got.  So what can i do to fix this problem of shinbang?  Ive landed back seat acouple of this but i dont think this is enough to give me this terrible pain.  Am i wrong?  Thanks for the help! and please no dumb answers.  Just helpful ones... Oh and i have small calfs and am 135 and 5'7