Thanks for the query to H.C.M. Forum.
Let me explain you that what is postural orthostatic Tachycardia Syndrome
This syndrome is characterized by symptomatic orthostatic intolerance ( not orthostatic hypotension
) and by either an increase in heart rate to >120 /minute or an increase of 30 beats / minute with standing that subsides on sitting or lying down.
Women are more sufferer of this disease in the age group of 15 -50 years.
Causes may be .
1 Antecedent viral infection as may in your daughter case as there is cough , breathlessness, chest pain.
2 Syncopal symptoms lightheadedness
, weakness , blurred vision
3 Autonomic over activity as palpitations,tremulousness , dysautonomia , fatigue.
My main aim was to highlight various symptoms of pots .
In my opinion your daughter is right and your daughter may be a patient of pots.
2nd reason of such symptoms may be asthmatics allergic bronchitis , diagnosis can be confirmed by physical examination with blood examination for eosinophils count.
, diagnosis can be confirmed by sputum examination and Montox test.
In my opinion consult an immunologist and get his opinion.
Good luck. Dr. HET