Hardware Left stick on pro controller is squeaky.

[Quadrotix]

whenever I move the left stick on my pro controller up or down, it makes the sound you’d expect to hear when rubbing kitchen roll against a window. It still detects every input perfectly, but the resistance makes it harder to move. What could be causing the problem? The controller is only 7 months old

 

[nantalos]

My guess is that there is some dirt inside.
You could try cleaning it with compressed air or rubbing alcohol (look up a tutorial on yt if you aren't sure how to).

Or if you still got the receipt you could have Nintendo or the place you bought it from repair or replace it.