If the dizziness is not positional, then your doctor might ask for further investigations, lab tests, imaging(CT scan/MRI), Audiometry, as diagnostic work up.
The symptom is caused by blood pooling in the lower extremities upon a change in body position. It is quite common and can occur briefly in anyone .well there are several conditions that might contribute to it such as :
hypovolimia (decrease in blood volume ) and dehydration
diseases such as diabetes
medications such as anti depressants
Vitamin B12 deficiency
try when you change position to get up slowly from a position to the other to minimize its prevalence
>another possible cause if the headache is throbbing is Migraine it can be associated with dizziness in some patients and you may feel somehow nausea
>ear problems if there is other associated ear symptoms may also contribute to this,if you had tinnitus(ringing in ears) in any or both ears or dizziness is like an attack of rotational vertigo that can be severe, incapacitating, unpredictable, and last anywhere from minutes to hours,beside fullness in either or both ears and some how decrease in hearing then this will be a disorder of the inner ear that can affect hearing and balance to a varying degree called MENIERE's disease
>if the dizziness is recently felt you may have an infection that is affecting your balance and show in this manner due to dehydration
>if you are a kind of women who don't drink that much fluids or have poor diet these symptoms might be seen too due to dehydration and lack of minerals and carbohydrates
>stress not having enough sleep might be a cause in the absence of other symptoms .