I've recently changed to an electric razor and now have noticed that my neck is itchy and a bit sore. Is there some sort of pre-shaving balm or moisturiser which I can use to help prevent this?
Your skin will need to get used to the new shaving regime - I've always used electric razors and have never had this problem.
Is it a foil razor? These tend to irritate necks more than rotary shavers. I've always used Philips rotary and have never had redness/irritation anywhere.
I think that cheapo electric razors (amazon, ebay etc) are a BIG mistake!
Stop pushing on the razor. Dry shaving with an electric shaver is a slow laborious process. Lots of gentle movement is necessary, but don't push hard on the skin.