I have had these internal tremors for years. The first time I noticed them was after my first pregnancy. It turned out I was anemic and b12 deficient. I supplemented and they went away. They came back after my net pregnancy and I was also b12 deficient with low iron. I supplemented and they went away.

Last year I developed POTS (postural orthostatic tachycardia) and these tremors returned even though my b12 levels and iron were fine. b12 and iron deficiency cause neurological symptoms such as vibrations and pOTS is a neurological auto immune disease.

Someone in another forum mentioned that it is related to shallow breathing and that possibly makes it worse. I have heard it is related to GERD. I cannot get any answers and nothing helps. I do take clonazepam when it is incredibly bad. I always get these tremors when I am having a poTs flare.