If she doesn't have free access to hay or grass all day, she needs to be getting more pellets. Young growing rabbits need to always have food to eat, as they need the nutrients.
If you believe the odd chewing behavior is not normal, and it's not just her munching on her cecotropes, then yes you should probably have a vet check her teeth, though it would be very unusual for her to have molar spurs at her young age. Not impossible, but it would be unusual.
Is the strange noise you are hearing, coming from her breathing and nasal passages? Could you describe the noise a bit more? Any sneezing or discharge at all? Is there matting on the inside of her front paws?