eheathDon't land/ski backseat, easy fix.
That's not helpful for OP at all, when you're learning new things you're guaranteed to land backseat a few times.
OP did you get your boots fitted by a good boot fitter?
Do you have custom made footbeds? Without good footbeds your feet won't be supported properly and this can lead to shin bang.
Did you get your liners heat molded?
Are you sure your boots are the right size - if you do a shell check do you have 3cm or more space between your heel and the shell?
If you're getting sore shins after just a few laps your boot probably don't fit properly and I'd take them to a good boot fitter and let them have a look just to ensure the boots are actually suitable for you.
I like to ski with loose underpants or boxers on so my balls can swish around and chill.