http://chronicfatigue.about.com/od/symptoms/a/brainfog.htm

Brain fog (also called fibro fog or cognitive dysfunction) is one of the most common complaints of people with fibromyalgia (FMS) and chronic fatigue syndrome (CFS or ME/CFS). For many, it can be severe and can have just as big an impact on their lives as pain or fatigue. In fact, some people say brain fog is more of a disability than their physical symptoms.

http://www.drlwilson.com/Articles/brain_fog.htm

Brain fog may be described as feelings of mental confusion or lack of mental clarity.  It is called brain fog because it can feel like a cloud that reduces your ability to think clearly.  It can cause a person to become forgetful, detached and often discouraged and depressed.

http://www.wisegeek.com/what-is-brain-fog.htm

It is estimated that brain fog affects thousands of people, contributing to a host of problems at school, at work, and even at home. It can contribute to low self-esteem and may cause or exacerbate relationship problems. Some people even assert that brain fog can lead to crime and delinquency as well.

http://www.myadrenalfatigue.com/brain-fog

One of the most common complaints for those with adrenal fatigue is brain fog. Even as a very common complaint, it is not a recognized illness in traditional medicine.  In addition to adrenal fatigue, brain fog is often associated with hypothyroidism, or menopause.

http://www.cfidsselfhelp.org/library/lifting-fog-treating-cognitive-problems

Most CFS patients and many people with fibromyalgia experience cognitive problems, often called "brain fog" or "fibro fog." The difficulties, which many people find very distressing, include being forgetful, feeling confused, difficulty concentrating and the inability to speak clearly.

http://drmyhill.co.uk/wiki/Brain_fog_-_poor_memory,_difficulty_thinking_clearly_etc

Brain fog - poor memory, difficulty thinking clearly etc

http://www.drlam.com/articles/adrenalexhaustion.asp?page=3

Four Phases of Adrenal Exhaustion

http://www.newtreatments.org/loadlocal.php?hid=1113

Brain fog includes symptoms of forgetfulness, spaciness, feelings of confusion and inability to focus and think clearly.  Many people have been this way for most of their life and think this is normal.  Brain fog can be due to hypoglycemia, candida overgrowth, chronic fatigue, food reactions, nutrient deficiencies, mineral toxicity, liver, kidney or bowel toxicity, poor oxygenation, structural misalignments, medications, genetics and other causes

http://www.drlam.com/articles/adrenalexhaustion.asp

Adrenal Fatigue, as a debilitating condition, is not recognized by conventional medicine and is thus missed by most conventionally trained physicians.

A condition in which the adrenal gland is compromised in its production of epinephrine, norepinephrine, cortisol, corticosterone or aldosterone. Symptoms include primarily fatigue, weakness, decreased appetite with ensuing weight loss, as well as nausea, vomiting, abdominal pain, diarrhea or constipation, or increased pigmentation of the skin. Cortical insufficiency (low or no corticosteroids) produces a more serious condition called Addison’s Disease, characterized by extreme weakness, low blood pressure, pigmentation of the skin, shock or even death.

http://www.arthritistoday.org/symptoms/fatigue/coping-with-fatigue.php

Fibromyalgia pain has no boundaries. People describe the pain as deep muscular aching, throbbing, shooting, stabbing, or intense burning. Quite often, the pain and stiffness are worse in the morning, and muscle groups that are used repetitively may hurt more.¹² In addition, the severity of regional pains (particularly those in the head, neck, shoulders and lower back) are a strong predictor of a person's overall pain rating.¹³ The muscles in these painful areas can feel tight, knotted and rope-like. Pressing on the firm, knotted region hurts and often causes the pain to shoot to other muscles when a myofascial trigger point is present.

http://www.ei-resource.org/illness-information/related-conditions/treatment-for-adrenal-fatigue%10adrenal-exhaustion/