All my life I have had issues with nerves in my feet or hands, sometime running up my arm or leg. It is not a pain but more of an intense nerve activation that can not be scratched. Heat is about all that calms it until I feel cool air which makes it react again. Happens about 2 to 3 times a year and lasts about 3 days. When this happens I can not sleep or do any physical activity as it sets it off. Any ideas what causes this?