I've posted about chakras before. I might have even mentioned them in my books. Chakras are so ubiquitous you don't even think about them -- you see chakra candles at Whole Foods, chakra gemstone necklaces at art fairs, you can buy Wiccan athames with chakra symbols on them and chakra smudge kits. As of this writing, the #1 search result for the word "chakra" on Google is a Healthline page. Chatting with a Nepalese-born clerk at a local shop, he was describing to me anxiety symptoms and termed the sensation as "hitting right in the heart chakra." Didn't even need to explain what that was.
In ancient medical beliefs, chakras were considered to exist inside the body. According to Ayurvedic medicine, the concept of the chakra is related to the wheel-like circulation of the body, believed to exist as the human double in the celestial plane. The spinning vortex of subtle matter is the focal point of energy absorption or propagation. There are many variations of these concepts in the Sanskrit sources. Earlier texts have different systems with the connections between them varying. Different traditional sources list 5, 6, 7, 8 or even 12 chakras. Over time, a system of 6 or 7 chakras along the body's axes became the dominant model, adopted by most yoga schools. This particular system may have been developed around the 11th century, and rapidly gained widespread popularity. It is in this model that the kundalini is said to "rise" upward, penetrating various centers to the crown of the head, resulting in union with the divine.
On this system, these chakras required intense meditation to unblock so that they could spin freely and help a yogi ascend to greater abilities. However, a variant in Buddhist belief interpreted the chakras as always at least partially open, and having the ability to influence one's thought and experience in everyday life.
It appears that the introduction of the chakras into Western new age practices happened with Helena Petrovna Blavatsky's book The Secret Doctrine, published by the Theosophial Society. In it, the role of the Pineal Gland and Pituitary Gland is discussed in the context of spiritual development. These glands she believed to be crucial for achieving higher states of consciousness and clairvoyance. The Pineal Gland is considered the "Divine Eye" or the seat of spiritual insight, while the Pituitary energizes willpower, and their activation through occult practices is said to enable profound spiritual experiences and knowledge. She posited that mastery of these chakras is key to spiritual advancement. The ultimate goal is to awaken higher consciousness, achieve union with the universal spirit, and transcend physical limitations through disciplined mental and spiritual practices.
Soon, new age texts began to talk about chakras as the key to gaining psychic powers and occult mastery (just like black cat bones used to offer, FWIW.) By mid-twentieth-century, even the US government was beginning to get excited about the idea of psychic ability, and actually sponsored experiments into the matter -- and so, chakras were suddenly talked about all over as some kind of "secret key to psychic power."
By the 1970s they were being referred to as "your psychic energy centers" and taken as a universal fact in new age magical texts from the ESP Lab, where the reader is told that blocked chakras will result in undesirable things like lethargy, poverty, depression, and flare-ups of chronic ailments. There is an implied supposition that the natural state is for a chakra to be open and it only closes due to some kind of contact with negative energy or though a personal failing. Gemstones and color therapy were suggested means to unblock them.
By the 1990s Doreen Virtue was writing whole books about Chakra Clearing, and how it could be done with "angel therapy" (which sounds close to the ideas of the ESP Lab spirits and their workings) and listing warnings about "foods that clog chakras." Which in a way is taking it full circle (full chakra?) back to the Ayurvedic system. A Reddit comment about the book complains: "I wouldn't believe a word she says. She just grabs everything even remotely spiritual and smashes it all together into an indistinguishable soup." Though of course the Redditor loses sight of the the fact that that is the whole idea behind much of the new age movement, the notion that all these practices from different systems and religions are equally true and maybe even all representative of the same things, ergo can and even should be "smashed together!" -- No "cultural appropriation" in this realm -- "There is no religion higher than Truth" as was the old motto.
Nowadays even Botanicas and Candle Shops sell chakra supplies. Like I said, they're ubiquitous. Even peddlers of spiritual products who sneer at non-traditional items will carry chakra supplies -- and fair enough, they've been part of the American spiritual landscape for over 100 years now. That's longer than Wicca has even existed.
While the origins of chakras may be in ancient East Indian medical beliefs that are now generally agreed to be discredited, they've moved into the spiritual realm, where they've taken on a new life. It's likely the mainstreaming of yoga as a type of exercise class contributed to chakras being taken for granted. Now they are aligned with medically valid nerve centers. Now they're what you can say you feel pain in when under social anxiety.
And if they are just bundles of nerves, then how can we not blame them for bodily ailments and mental distress?