Why are my trigger buttons triggering when I squeeze the controller.

So I have a controller that’s a few years old, recently broke out the old ps 4 pro and wanted to play a few games with it. Every time squeeze the controller firmly or hard it weirdly sets off the trigger buttons (L2/R2). And sometimes it just gets stuck that way. Also noticed that press down on the analog sticks can just set them off too. Tried resetting it and taking it apart to blow some air around inside it to clean it up a little. Still the same problem. Does this mean the controller is completely broken or is there a way to fix this sort of problem?