Hypothyroidism: Given the patient's perimenopausal status, persistent fatigue, trouble sleeping, and general soreness, hypothyroidism is a common condition that could explain these symptoms. The normal ferritin and high cholesterol despite a healthy diet and BMI also support this diagnosis, as hypothyroidism can lead to increased cholesterol levels and fatigue.

Anxiety or Depression: The patient's trouble sleeping and general soreness could be related to anxiety or depression, which are common in perimenopausal women. These conditions can also contribute to fatigue and should be considered in the differential diagnosis.
Fibromyalgia: This condition is characterized by widespread musculoskeletal pain, fatigue, and sleep disturbances, which align with the patient's symptoms. Fibromyalgia is more common in women, especially during the perimenopausal period.
Adrenal Insufficiency: Although less common, adrenal insufficiency can cause fatigue, sleep disturbances, and general soreness. The normal ferritin and high cholesterol do not rule out this diagnosis, and it should be considered, especially if other symptoms such as orthostatic hypotension are present.

Sleep Apnea: Although the patient reports trouble sleeping through the night, sleep apnea is a condition that should not be missed due to its potential to cause significant morbidity and mortality. It can lead to fatigue, soreness, and other symptoms reported by the patient.
Lymphoma or Other Malignancies: While less likely, lymphoma or other malignancies can cause persistent fatigue, night sweats, and general soreness. A negative CRP does not rule out these conditions, and they should be considered, especially if other red flags are present.
Chronic Infections (e.g., Lyme Disease, Endocarditis): Certain chronic infections can cause persistent fatigue, soreness, and sleep disturbances. Although less common, these conditions are critical to diagnose and treat promptly to prevent long-term complications.

Mitochondrial Myopathies: These are a group of rare genetic disorders that affect the mitochondria and can cause fatigue, muscle soreness, and sleep disturbances. While unlikely, they should be considered if other diagnoses are ruled out and the patient's symptoms persist.
Porphyrias: This group of rare genetic disorders can cause a variety of symptoms, including fatigue, soreness, and sleep disturbances. They are often diagnosed late due to their rarity and non-specific symptoms, making them an important consideration in the differential diagnosis of persistent and unexplained symptoms.