Why is my new controllers analog stick dragging

So I recently bought a new controller because my old one didn’t work well. I noticed almost immediately that the left stick was dragging up almost constantly.(It wasn’t actually dragging up but the controller would register that it did) do when I was playing a FPS for example my aim would drag up. Occasionally this stops happening and it might stop for hours before it happens again. Does anybody know a way to solve this outside of buying a new controller/analog stick.