I had an internal vibration right under my sternum last night cooking dinner! I definitely pushed my limits yesterday doing too much. I immediately sat on the kitchen floor once I felt this strange feeling, but knew I would be fine since I have already had every cardiology and neurology test under the sun. Thank you for putting a name to it. I also experience severe sensory overload, sometimes I am unable to take a shower because my nervous system is overloaded from feeling the water on my skin.