I just responded to utleezard's question. Although that response is partially applicable to you, I would like to point out a very important difference: You are having chills and sweats.
While there are a number of possible interpretations of your symptoms, the most straightforward is that you have either an infection or a rheumatologic condition.
In my experience, the most common location of a hidden infection is the ears and sinuses. In men, chronic infections/inflammation of the prostate is often responsible. In women, chronic pelvic inflammatory disease may be the cause. People with kidney stones may have a chronic urinary tract infection that is very difficult to diagnose or treat. A relatively common cause is "cat-scratch fever," usually acquired (surprise!) from a cat scratch. I have seen cases of similalr symptoms caused by long-standing lung and other abcesses . Tuberculosis and related diseases are not uncommon. Certain viral infections of the liver (especially chronic hepatitis B and C) are possible causes. If you have been in a part of the world where malaria is common, that should be considered. Cellulitis should be obvious, but it is usually overlooked and usually misdiagnosed when seen. Fungal infections are unlikely causes, but they can be difficult to recognize.
I have less knowledge about the rheumatologic conditions, but I would mention lupus erythematosis, Goodpasteurs' disease, midline granulomatous disease, Wagner's granulomatosis, sarcoidosis, the various conditions causing inflammation (vasculitis) of the blood vessels, and even garden-variety rheumatoid arthritis.
From the endocrine perspective, flushing and sweating ("hot flashes") followed by chills as the sweat evaporates are common with deficiencies of the sex hormones (Think of a woman going through menopause.) They are also seen with an excess of thyroid hormones. I do not get the feeling that you are describing an endocrine disorder, however.
Is there a connection between your symptoms and the family history of thyroid disese? Perhaps. Most cases of thyroid disease are autoimmune, meaning that the body's own immune system attacks it. Autoimmune diseases tend to run in families, but not necessarily the same autoimmune disease in various family members. Likewise, the rheumatologic diseases are autoimmune disorders.
You did not mention how you determined your body temperature. You probably know that this should be measured under the tongue with the mouth closed, but you may not know that it should be measured in the very sensitive pocket at the back of the tongue. Unfortunately, if it does not hurt, it's not the right place.
I hope that this is helpful to you and to utleezard.
M. Shank, M.D., Ph.D.
Diabetes and Metabolism Special1st Care (sm)
715 W. North St.
Lima, OH 45801