Chakras seem to be associated with healing and harmonic overtones. Where did this all come from?
Chakras are from Vedic medicine and refer to both physical body and what is called the etheral body. Aryuvedic medicine is based on balancing chakras in order to achieve a harmonious and healthy state. Here is a quick link, but the wiki articles on chakras are quite weak. Let's find a good one.
https://simple.wikipedia.org/wiki/Chakra