Thanks for your question.
Basically these symptoms may be caused by many underlying disorders. Dizziness when lying down is usually caused by a viral ear infection. This may also cause other symptoms such as a feeling of pressure inside your ear or tinging or humming in your ear
However other causes such as low blood pressure, anemia, dehydration, or even anxiety may sometimes cause these symptoms. Therefore an examination by your doctor to know the specific cause and then its treatment will be beneficial. If this was due to a viral infection then the symptoms will resolve within a few weeks. However self help measure to avoid a fall such as sitting or lie down immediately when you feel dizzy will be beneficial. Therefore though this is a self limiting condition still an examination by your doctor is required for diagnosis and for medications to minimize the symptoms.
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