What causes my son to sometimes make really high pitched noising while breathing during his sleep?

Nosiy breathing -kid: If your child is havign noisy brreahting in sleep you hsould have him checked out as it could be snoring vs a floppy airway. Your pediatrician should lsiten to him and if necessary will refer yo to an ENT md.

Many causes: It may be helpful to record the sound and to have your pediatrician evaluate him. Snoring, nighttime cough/wheezing/stridor are some possible causes. Some of the tests to consider include a pulse oximetry and/or a sleep test. If he has a history of asthma/allergies there are multiple treatment options available.