That's normal, you will need some muscle power to press the dough through the potato ricer. I also recommend using a quality potato ricer. Apply your physics knowledge here and press down at the handle ends, and you will see it will be easier. It also helps to keep the mass out for 2-3 minutes, after it has cooled in the fridge, so as to "warm it up a bit. But don't keep it out too long because soft passatelli mass increases the risk of the Passarelli's breaking in the broth during the cooking process.