Neck tremor and slight headache

Does anyone else have these symptoms? It seems as I get closer to the date I need my IVIg I start to feel this weird tremor or vibration in the back of my neck and it is usually together with a mild headache. I notice it more when I am laying down on my pillow trying to go to sleep. It is a very mild tremor. You can’t see my neck or head move but I feel it inside. It is annoying to say the least. It usually subsides a few days after I get my IVIg infusion and stays away for about one or two weeks returning about day 14 or 15 post IVIg. Other than that I feel good. I was wondering if CIDP can cause these symptoms or if something else is going on. Maybe it is anxiety induced? But it seems weird it happens around the same time after my IVIg seems to start to wear off. Just wondering because it is causing me some anxiety.