chase your tail

chase (one's) tail

To take action that is ineffectual and does not lead to progress. Refers to how a dog can exhaust itself by chasing its own tail. Come on, Bill, go to sleep. You're just chasing your tail at this point, but you might have a breakthrough with the research if you take a break from it. I'm trying not to chase my tail on this project, but so many components of it are just not working out.
See also: chase, tail

chase your (own) tail

keep on doing something futile. informal
See also: chase, tail

chase your (own) ˈtail

be very busy but in fact achieve very little: In my first month at college I was continually chasing my own tail and being late for everything. ▶ ˈtail-chasing noun
If a dog or cat chases its tail, it runs round in circles trying to bite its own tail.
See also: chase, tail