Part of the problem is the helmet/goggle system. We had a number of pilots in our company starting to complain about neck pain when using the Alpha Eagle helmet (the pilots had been regularly flying on NVG's for a few years).
A couple of years ago we switched to Gallet helmets and most of the neck pain complaints stopped. I noticed a difference myself. The goggles/helmet feels much more balanced with the Gallet, therefore its less fatiguing to wear (and no, I don't work for Gallet or a Gallet supplier!
).
Cheers.