You probably won't believe me but I will throw this out there anyway. That pain in the neck after 30 miles or so is a classic symptom of magnesium defficiency. We don't get enough magnesium in our diets these days and exercise depletes what magnesium we have so after a decent ride we just go into deficiency.

Magnesium is a muscle relaxer so when you become deficient your muscles start tensing up and that pain in the neck is the first place I start getting it too.

Here's a reference on Magnesium, http://www.healthy.net/asp/templates...Article&ID=541

It talks about serious magnesium defficiency but it has to start somewhere. Calcium and Magnesium are antagonistic so I would be avoiding too much dairy/calcium foods when exercising.

Regards, Anthony