I get it too. I have lost a lot of weight and my BG levels are mostly within the normal range, but I do still get those little sharp pains.
It seems that you have to look after your feet as carefully as you look after your diet. Lots of washing with a brush, applying potions and lotions, massage, keeping the feet warm and comfortable seems to be the order of the day. Treat your feet like the most pampered and annoying cat you ever came across and it will ease.
Plus, keep well hydrated.
I think it is worse at night because the feet are more relaxed. The simple process of waking around the house keeps the blood flowing. As soon as you sit down and relax though, arghhh.
There are some dos and don'ts on this page,
http://www.wecare.ca/blog/?p=562
This may be of use too:
7 Steps to Healthier Feet for Diabetics