i got previous posts about this.. i had it REALLY bad last year.. like, real bad.
i bought some special foam tongues from some company (try masterfitU@aol.com) if that email addy is wrong then go to your ski shop and ask them for custom boot tongues that you can insert into your boots. that helps like a whole bunch. also soften up your boot a bit and dont put the cant all the way forward it really doesnt help. get a booster strap too.. arnica cream helps also when they hurt.
what boots do you have anyways?
Make sure your socks are high, dont hit shitting jumps, AND DO UP YOUR BOOTS TIGHT, do up the power strap at the top tight, no one uses it, but the space between your calf and boot is a main source of shin bang, do that up tight to reduce space