In most cases, a shaking chill is a mechanism to raise body temperature by increasing the activity of muscle cells. As they contract, do work, the cells generate heat, much as an auto mobile engine generates heat as it does work.
So, what is putting out a call for help by raising the body temperature? Usually this is the presence in the body of a foreign protein such as a bacteria, their toxins, or viruses. Unusually, it is another type of invader that we generally do not test for. The purpose for the increase in body temperature is that the higher temperatures help the immune system inactivate and kill them.
I would not look first at the shaking, I would consider your problem a fever of unknown origin (FUO). The muscle contraction is only a means to an end. Why do you need to have an increase in body temperature?
The following is copied from this source:
- Although infections are the most common causes of elevated body temperature, fevers have a long list of other causes, including toxins, cancers, and autoimmune diseases.
Please go to the linked page. You will see elaboration of what I have told you, with a long list of possible causes that should be investigated for you.
I recommend that you see a good internal medicine doctor with experience in infectious and autoimmune diseases, who knows how to deal with FUOs. I doubt that a family practitioner would deal with this often. Also, ask him to see if he can shorten your mediation list.
Tell me where you live in North Carolina so that I can help you find a specialist if necessary. If you are close to any of the excellent academic medical centres in NC, that may be your best bet.
There is another possibility you may explore, although it would take longer and is my second choice. You can have your doctor look at the list of causes in the link and arrange for appropriate tests for all, and send samples drawn under your normal circumstance, during a chill, and when your body temperature has risen, for blood cultures to the Centre for Disease Control and Prevention (CDC) in Atlanta, GA, to test for rarely seen entities.
This is the protocol at my university medical centre. We have excellent clinical and research laboratories, but there are tests that are so infrequently needed that, unless one of us has set up to do them because of a special clinical and research interest, we send them out.