There is a condition called "Stridor" which may present as the high-pitched breathing sound. It often appears when baby is 2 weeks old and baby will outgrow it.
Here is a video with some general information on it (not sure if it's the same as what you are hearing, so you can take a look at the video):
http://fox17online.com/2015/01/06/medical-moment/
Other treatment option include having a surgery.
Hope this helps!
Read more
Momsy of two