Hi, welcome to the ehealth forum and I am glad to help you.
You seem concerned by feeling hot without fever and also feel cold at night. You have made a mention of having received treatment for kidney stone along with kidney infection and now off all the medications.
Chills with fever suggest that your body is fighting some infection but chills without fever as you seem to be suffering from may indicate hypoglycemia, anemia, thyroid disorder, anorexia nervosa or another medical concern. As for the relationship to food, it is possible you are having a food allergy, sensitivity or even hypoglycemic response. However, because much more information is needed, you should get a complete medical evaluation by your personal physician.
Hope this helps. Take care.
Note: This post is not to emphasise final diagnosis as the same cannot be made online and is aimed just to provide medical information and no treatment suggested above be taken without face to face consultation with health care professional.