Hello thank you for trusting HCM Dear the term “chills” refers to a feeling of being cold without an apparent cause. You get this feeling when your muscles repeatedly expand and contract and the vessels in your skin constrict. Chills can occur with a fever and cause shivering or shaking. some chills may accure after exposure to cold environment and some due to bacterial and viral infections. bacterial or viral gastroenteritis,flu,meningitis sinusitis,pneumonia,strep throat,urinary tract infections (UTIs),malaria etc... only chills may not need to consult your doctor,drink plenty of water, covering body with smooth cloth is enough. but if you develop cough, burning micturition,neck stiffness, vomiting along with chills you need to consult your physician he will examine and treat you accordingly. take care