I used to have that problem too!My house dont know full of what pest. Look like ants, but so tiny, is abit light grey. Crawl all over the walls. Not sure got something to do with wall paint? They like to stick all over walls and stop moving.
Put ants poison but seems not useful. They seems afraid of lavender smell. Anyone got this pest too can share how to get rid of them?
I called up Pest Control Company to fix my problem.