Research in the International Journal of Yoga found that chanting can lead to significant deactivation in the parts of the brain responsible for stress. It is believed the vibrational / neurophysiological effects of ‘AUM’ chanting may be mediated through the branches of certain nerves that run through our ears that are part of our “good” nervous system. The findings also showed that ‘AUM’ chanting indicated a reduction in the part of the brain that deals with many things such as emotions and arousal.

During pain episodes the “bad” nervous system fires up and we release tonnes of stress hormones and various unpleasant emotions in addition to the pain already experienced. By reducing the activity in the part of the brain that thinks it is under threat from the pain, you have a tool to hopefully reduce pain sensations and to generally become more calm all round.

My favourite chant from my Yoga Therapist @ Ray of Light Yoga is:
Om Namo Namah pronounced “Om Nah-More Na-ma-ha” meaning “It’s not me” invoking that there is a separateness between you and your pain…enjoy

For a more detailed account:

Reference : Bangalore G Kalyani, Ganesan Venkatasubramanian, Rashmi Arasappa, Naren P Rao, Sunil V Kalmady, Rishikesh V Behere, Hariprasad Rao, Mandapati K Vasudev & Bangalore N Gangadhar (2011). Neurohemodynamic correlates of ‘OM’ chanting: A pilot functional magnetic resonance imaging study Int J Yoga Jan-Jun; 4(1): 3–6. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3099099)