Hi and thanks for the query, Low grade fever especially at night deserves a careful evaluation. This could range from infectious causes like tuberculosis, sarcoidosis or other bacterial infections. Inflammatory diseases must also be considered. The symptoms observed in the arms could certainly be associated either to a compression of the nerves in the brachial plexus, which supplies nerve innervation to the upper limbs and could be simply due to a bad position taken during sleeping. Carpal tunnel syndrome might also be a probable source. Vitamins and at times steroids might necessary depending on the case. a careful physical examination and blood tests, with an X ray might be very useful in the evaluation. I suggest you take an appointment with an internist. Thanks and best regards, Luchuo, MD.