When your body is hot but you're feeling cold it's usually because of what's known as myalgias which is a term used to describe body aches and generalized muscle pain.
The body aches and generalized muscle pain can be cause by some form of infection in your body or could be just due to the flu.
If you don't have other symptoms of the flu then you should go see a doctor to find out exactly what's going on with your body.
Because the infection could be serious and then again it may not but it's best to find out for sure and get the infection treated if it isn't the flu.
When you have the flu though it's very normal to feel hot with a fever but have chills and shiver and feel cold.