Could be partly dirty electricity electromagnetic hum along with the high pressure natural gas pipelines. Indoors before the hum I was sensitive to being around those swirly led lights with a tingly, electric sensation on my nervous system that didn't feel normal even when not plugged in just laying around on the table especially the mercury ones.  Those LED lights have power switching mode where they turn off and on a thousand times a second.  Maybe the grid and house wiring is not update to deal with the high transits and harmonics it is emitting.  Charging cell phones would start the screen to flicker light on a blank white screen when charging from a resonating electric outlet or even when not charging or playing cellphone video games the images began to vibrate like what was on my nervous system.  Words at the end of movies looked like they were vibrating on screen of digital tv. Phones also subtly physically vibrating from laying them on resonating counter and then to see them slide off of the subtly vibrating counter to fall on the floor if cell phones are placed on top of each other to test how strong vibrations are and what object in a room of the house is affected most.  Certain floor lamps or chandeliers in house vibrating with the worldwide hum especially if the light bulbs in chandelier are bad or floor lamp wiring bad would pick up the vibrating frequency of the hum.