I have this problem as well. It started about 2 years ago, when early one morning I woke up because I had horrible vertigo. Though, instead of the traditional vertigo where it feels like I'm spinning around, I felt like my head was shaking back and forth very quickly. It went on for about 2 months, and literally every time I laid down and closed my eyes, the vertigo would happen again. Though, when I opened my eyes, it would go away. I'd occasionally feel numb in my arms from my elbows to the tips of my fingers in both hands.
Over time, the problem has died down a little bit, but happens maybe once a week. I've actually gone to doctors several times. I was tested for everything from Benign Paroxysmal Positional Vertigo to being prescribed anti depressants. The ENT doctor I went to see told me it was probably caused by eating too much salty foods. But when I cut back on salt, the problem was as bad as ever. I'm a young female, 23 years of age. And I'm getting to the point where I just give up on seeing a doctor, because out of literally the 10 different doctors I've gone to see, none of them seem to know what it is, or how to treat it. So, they give me motion sickness medicine and send me on my way.