Intermittent head pressure esp behind eyes, clogged ears, tight jaw. cbc, echo, ekg ok. lowering head worsens pressure. allergies? musculoskeletal?

Pressure in head: in a young lady may be due to deep sinus problems or Idopathic intracranial hypertension especially if there is a positional component. I would see a neurologist. Check Iron level, Vit A level Thyroid function if there is evidence of raised intracranial pressure on fundoscopic (eye) exam. also check a CT of the head.. I wish you best of health.