Share 'Rage, allergies or something else?'

I'm not sure how to ask this, but we have reached a point where our entire family is at a loss.  My son is 7, but has had severe headaches since he was old enough to tell us about them.  He has also had digestive problems (much of which manifest as severe constipation) since he born.  We have been to doctors and still, no answers.  An allergist was unable to get a good test because he did not rea…