LOCATION
The solar plexus chakra is located in the hollow area between the ribs. The posterior solar plexus is located behind the anterior solar plexus. The term solar plexus chakra means both the front and back solar plexus chakra.

SPIRITUAL FUNCTIONS
Subtle energies from the lower and upper chakras pass through the solar plexus chakra. The will centre of the masses is located in the solar plexus chakra. A person has the option of following the impulses of the lower nature or the will of the higher soul. When man's lower will is aligned with the will of the higher soul, man walks the path of Tao or the spiritual path of righteousness. One's inner strength increases because he is under the influence of his higher soul.
PSYCHOLOGICAL FUNCTIONS
The solar plexus is the centre of both positive and negative lower emotions. Positive lower emotions include ambition, boldness, courage, perseverance, strength, righteousness, justice and fairness. Negative lower emotions include anger, irritation, hatred, envy, greed, destructiveness, violence, cruelty, resentment, worry, anxiety, tension, fear, selfishness, aggression, abrasiveness, addiction, etc. The term "lower emotion" is not necessarily bad. The solar plexus chakra, as mentioned earlier, is also the centre of courage, boldness, strong drive, perseverance and the will to win. This is the centre of "Ego", as in "I want this, I want that, I need that ....". To be successful, the solar plexus chakra must be strong. It is the center of assertiveness. In general, the masses are emotionally driven. Therefore, the solar plexus chakra is where the lower will lies; it is the centre of the will of the masses. This is why in Kabbalah the solar plexus chakra is also called 'The Force'. In more developed people, the centre of the will is located in the Ajna Chakra, which is the active intelligence. In healing psychological conditions, the solar plexus chakra is usually, if not always, treated. When a person is stressed or harbours a deep grudge against other people, the solar plexus chakra becomes congested with dirty red energy.
PHYSIOLOGICAL FUNCTIONS
The solar plexus chakra and navel chakra control and energize the gastrointestinal system. The solar plexus chakra controls and energizes the diaphragm, pancreas, liver and stomach. It is easier to energize the pancreas through the solar plexus chakra in the back. To some extent, the solar plexus chakra energizes the large and small intestines, appendix, lungs, heart and other parts of the body. The solar plexus chakra also affects the quality of the blood as it controls and energizes the liver, which detoxifies the blood. Through the liver, it controls cholesterol levels in the body and therefore affects the condition of the heart. This chakra also controls the heating and cooling system of the body. The whole body can be energised through the solar plexus chakra. An exhausted person can be revitalised quickly by energising the solar plexus chakra.
SOME CONDITIONS CAUSED BY AN ABNORMALLY FUNCTIONING SOLAR PLEXUS CHAKRA
The solar plexus chakra can be easily disturbed or unbalanced by negative emotions. In many cases, negative emotions are one of the critical factors, if not the most critical factor, in serious conditions. The solar plexus chakra is the centre of lower emotions. Because most people are quite emotional, the solar plexus chakra tends to get quite dirty and malfunction. The problem caused by unregulated emotions is compounded by the fact that we live in a very stressful world. The solar plexus chakra is located in the centre of the torso; it is therefore very close to most of the vital organs. Malfunction of the solar plexus chakra tends to negatively affect the organ or organs close to it. The solar plexus chakra is either depleted or quite congested. Sometimes the front solar plexus chakra appears to be normal, but the back solar plexus chakra is quite congested. Patients with this type of condition tend to be tactful and usually do not express negative feelings. When a person is very angry, the solar plexus chakra pulsates irregularly. This causes the diaphragm to move irregularly, leading to irregular and shallow breathing. Anger and intense worry devitalizes the entire energetic body, so the body becomes susceptible to all sorts of illnesses. Negative emotions cause disturbances in the energy body, so that the whole physical body becomes ill.
Withholding or explosive expression of negative feelings for an extended period of time can manifest itself by:
1. glaucoma
2. migraines
3. acute sinusitis
4. hyperthyroidism
5. respiratory conditions such as asthma
6. heart disease
7. diabetes mellitus
8. gastric or intestinal ulcer
9. high cholesterol
10. damaged liver (negative emotions weaken the body and the liver, making it susceptible to infection).
11. constipation
12. twisted intestine
13. affected kidneys
14. hypertension
15. rheumatoid arthritis
16. cancer and others
When a person is physically violent, the solar plexus chakra, base chakra and meng mein chakra become over-activated. But the main chakra that influences the other chakras is the solar plexus chakra. A negative emotion can manifest as one type of illness in one patient, but it can manifest as another type of illness in another patient. In many cases, malfunctioning of the solar plexus chakra due to prolonged negative emotions tends to cause malfunctioning of the base, navel and spleen chakras. This manifests itself in severe arthritis. Hypertension can be physically caused by kidney malfunction or other external factors. In most cases, the cause or causes are not medically known; this is called essential hypertension. It can be controlled, but is assumed to be 'medically incurable'. From a Pranic Healing point of view, essential hypertension is caused by overactivation of the meng mein chakra, which is usually caused by overactivation of the solar plexus chakra. In other words, essential hypertension is predominantly emotional in origin. Through repeated pranic treatments, the patient's blood pressure can be normalised.
FORGIVENESS AND LOVE - KINDNESS
Some serious conditions are emotional in origin. Some people have a lot of pain or deep-seated resentment towards certain people. Although Pranic Healing greatly improves the patient's condition, the rate of healing would be much faster if the patient made a conscious effort to forgive those who have hurt them in real or imagined ways. Even if the solar plexus chakra and the other chakras are quite clean after the Pranic Healing treatment, if the patient remembers the person(s) who hurt him/her or the disturbing event, the solar plexus chakra will become congested and dirty again, which will also negatively affect some of the chakras and some of the organs. If the patient does not learn to forgive, healing will be slow or there will be a relapse. THE ACT OF FORGIVING IS THERAPEUTIC AND NECESSARY FOR GOOD HEALTH. It helps to normalise the solar plexus chakra and other affected chakras. Being habitually critical, irritable or angry is also very unhygienic (for one's energy) and bad for long-term health. The remedy is, of course, to learn to appreciate the good qualities of others, practice kindness and learn to be calm. It's easier to wear a pair of shoes than to try to flatten all the rough ground. It's easier to be kind, tolerant and detached than to try to change and improve everyone.
APPROPRIATE EMOTIONS AND THOUGHTS (EMOTIONAL AND MENTAL HYGIENE)
Proper emotional and mental hygiene consists of internal and external hygiene. Internal emotional and mental hygiene simply means appropriate emotions and appropriate thoughts. Positive emotions and thoughts such as happiness, kindness, joy, enthusiasm and others tend to have beneficial effects psychologically, etherically and physically. External emotional and mental hygiene involves proper companionship because emotions and thoughts are transmissible. Negative emotions and thoughts are contagious. This is why, after talking to people with psychological problems, you may feel depressed and physically exhausted. Prolonged interaction with this type of person can manifest itself in physical ailments. This is why many priests, nuns, social workers, psychologists and psychiatrists, after interacting closely for many years with people with psychological disorders, tend to become psychologically damaged and physically ill. It is also preferable to be sexually selective, as it is very easy to become etherically and psychologically contaminated through indiscriminate sexual interactions. After such interaction, it is advisable to cleanse yourself physically, etherically, emotionally and mentally. Food should preferably be handled and prepared by people in good health and in a cheerful mood, as good and bad energy can easily be transmitted into food and objects. Interaction with optimistic, enthusiastic, radiant and very healthy people is very beneficial psychologically and etherically. In the presence of an advanced spiritual master, one can easily be uplifted emotionally, mentally and spiritually if they are receptive enough and given the proper respect. Students actually bathe in the powerful aura of the spiritual teacher.
This information has been extracted and translated from the book of Master Choa Kok Sui (Founder of the Pranic Healing system) - Chakras and their functions