Eating anything more substantial than water or fruit makes me break out into a neck rash?

Food allergy? You could be allergic to some items of food; the common allergenic foods are egg, milk, nuts, fish, and shell fish. Try to correlate one introducing one item per week and the appearance of a rash. When the rash is limited to neck, think about contact with ornaments or allergic reaction to chemical sprays; the food may just be a co-incidence.