All chakra activating practices, according to traditional approaches, that is, the classical yogic approaches, require safe and gentle exercises to assure healthy progress. Traditionally, ‘shambhavi mudra’, the practice of breath + meditation + chant + particular posture + visualization is the standard go to for 3rd eye focus. This in conjunction with basic ‘pranayama’ and lifestyle practices. Pressure in the head is a tell-tale sign of force and you should back off of practices that are leading to that. Practices of ‘force’ which stimulate the body into activation mode such as holding the breath or intentionally creating pressure at various locations in the body can cause more harm than good if you don’t know what you’re doing and/or disregard the signs of imbalance. Headaches, for instance, are not a good sign. For your reference:

Regarding the pathophysiology of cerebrospinal fluid, disruption of CSF homeostasis can result in overproduction or decreased absorption of CSF, both of which may result in pathologies; one of interest is hydrocephalus. Obstruction anywhere in the ventricular system may result in increased intracranial pressure, which can create cascades of brain abnormalities, including cell death, inflammatory cell response, and cell shedding from the ventricular wall, or manipulation of the biochemical response of the cells.

That being said, please understand that if you are generally healthy, your spinal fluid is flowing precisely as it should, and nothing in the yogic practices encourages you to modulate that flow in any way. When the yogin talk about something rising upward from the pelvic floor into the third eye, we are speaking about ‘prana’, the life force, energy, a very subtle air – not a fluid – and it is not forced with pressure, even if some practices call for a very minor pressure to be exerted at the perineum either by placing the heel of your foot there during some yogic asana, or with a gentle squeeze and hold, called bandha, during other practices. Nothing is to be forced, friends. Slowly gently is the way.

Occam’s Razor

Reiki is not generally a forceful practice, making use of the body’s natural generation of thermodynamic energy and visualization coupled with non-local delivery of intention. There really isn’t much in the way of a physical or mental practice that can be considered forceful, unless too much concentration gives you a headache, but there’s no real danger to that. Observe yourself. The simplest explanation is usually the correct one. Be gentle with yourself and your practices. Are you holding stress? Do you know what you’re doing? Or are you following a YouTube tutorial blindly? Be careful. Treat yourself with integrity. Be impeccable with your approach. Feel your way at all times and let your mind be a trusted tool to help you discern the goings on in the various sheaths of Self.

Frequency Modulation and the Electromagnetism

The connection between Nature rhythms and the body is an established fact on too many levels to go into, and yet the science of objectivity still does not bear out certain things in the lab. EM correlation has garnered a lot of interest, and logic alone whispers of a mysterious potential in the interaction of forces, but statistics aren’t very revealing yet. This by way of saying that there are generally ready explanations for most conditions of imbalance without invoking the vaguely verifiable, or worse, the downright ludicrous.

By all means, stay true to your sensibilities. It’s actually not difficult to find rational and verifiable causation for most observed results. Let’s leave outliers by the wayside acknowledging that they exist, while understanding that they are called outliers for a reason. William of Ockham was actually quite a bright fellow and it’s fellows like these that we should enjoy learning from.

Frequency modulation on the other hand deserves a bit of your attention. Running the gamut between Beta and Gamma wave output can be quite exhausting to some and easily put an unsuspecting body off balance, too. ‘Trying’ to meditate can often create more stress than it relieves as we ‘try’ to maintain a posture and end up putting more tension into our shoulders and jaws than were there before we started, or causing ourselves to hyperventilate with breathing practices approached too passionately.

Consider also the flight between alpha and theta states with a quick return to beta when you open your eyes and engage the world immediately. If diving too deeply can bring on narcosis due to nitrogen buildup in the brain, or the bends from too rapid of an ascent back to surface, it’s not a stretch of the imagination to consider that the same may be said of psycho-physio forays into the depths as well.

Take care; do your research. Be observant and aware. Slowly, gently. No hurries, no worries. You’ll definitely reach the goal.

Sources:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6057699/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5180106/

https://www.uofmhealth.org/health-library/abo0894