How can breathing help with pain?

Yes some people can you breathing techniques to diminish the severity of pain. Sometimes holding your breath after a deep aspiration helps. This may not work on everyone.

A series of deep and slow inspirations and expirations may ease anxiety and tension temporarily. Meditation is based upon breathing techniques to create "mindfulness", and has been used for centuries to control injury induced pain, but also ongoing chronic pain conditions secondary to medical illness. Doesn't cure disorders but helps to cope.