Pressure is normally the cause, you are correct in your thinking. Another thing you may do is let your beard grow a bit and study it. Most of the time on our neck our hair around the adams apple will go in all sorts of directions. I can't shave from the outside in around my adams apple or I will end up just like you...shaving against the grain. Map out your beard and shave with the grain and across the grain...this is what I do on the neck around the adams apple.