Both characters have the step radical 彳 and only appear together — a bound pair. They paint a picture of restless, undirected movement, both physical and emotional.
徘徊 is very literary and evocative. In modern Chinese it's used figuratively: prices 徘徊 (hover), emotions 徘徊 (waver), someone 在...之间徘徊 (wavers between options). It always implies uncertainty or restlessness.
