What causes constant headaches, dizziness, numbness, pressure in head, weakness, fatigue, muscles aches, stuttering, brain fog, blurred vision?

See your doctor. or a your neurologist for evaluation, can't draw conclusions.
Fibromyalgia. 21 yo female complains of fatigue, confusion, dizziness, headaches, parasthesias, myalgias & vision change. General medical workup needed; if no distinct finding, then Fibromyalgia becomes a consideration. In young females childbirth, lumbar/pelvic injury, prolonged sedentariness & Hypermobility Syndrome are potentially etiologic for this multifactorial disorder. Osteopathic opinion might benefit.