Why does eating tomato products cause me to have chills, fever and days worth of vomiting ?

You may have a food allergy or intolerance to tomatoes. Sometimes it is the raw vegetables and not cooked product like ketchup or tomato sauce. Would follow up with allergist and see if you have issue with other vegetables from the same group( nightshades) like peppers, eggplant and potatoes.

In general the "Why?" is not easy to answer. We just note that Human Beings sometimes become intolerant or allergic to foods, drinks and items the had tolerated previously without issues. The indication is to pay attention to one's signs and symptoms and if tomato products cause symptoms avoid them or see the Allergist