I agree with deedee1981. Do you have any other symptoms? It wouldn't hurt to have it checked out especially if it causes you problems, like the chills.
Body temperature can vary throughout the day, being lowest in the morning, and some people have a regular temperature that varies from the normal. Low thyroid hormone (hypothyroidism) can cause a low body temperature. Diabetes, anemia, low or high cortisol levels, lyme disease or an infection could also cause fluctuations or variations in temperature. If you are concerned you could go to the doctor and have some tests done. Goodluck!
I almost don't want to know!! The reason is I have the same, and always have had! Though generally I have good health and am strong and fit.....