I am travelling and in japan,two days before i felt very cold and later got high fever 104 f,with lot of shivering and weakness,it happened suddenly s?

Viral Illness: This is probably infectious, probably viral. Try acetaminophen or aspirin for the fever. If your symptoms stabilize, it will take a week of bedrest to recover. If you develop shortness of breath, pain, or diarrhea, you need to go to the ER. Good luck

Traveling where?: Have you been in any malaria areas? India? Viet Nam? Borneo? etc. 104 is very serious. Suggest see a medical professional without delay.