I am 27 yrs unmarried man .When i Was in 7th standard(15 yrs back),I fainted in morning assembly twice.Then again in 12th standard(11 yrs back) I fainted in morning assembly (all the time in morning sunlight,8-9AM). I consulted one doctor and did not faced any problem for last 11 yrs.(During this time I din t have to attend any morning assembly in sunlight). After 11 yrs of last fainting incident, I again fainted some days back(this time in evening and not in sunlight).Doctor had my ECG , CT Scan of brain,Blood test, blood thyroid test, Echocardiography test done.All test were negative except some findings in ECG.On the basis of ECG doctor asked me to get 24hr holter monitoring and headup tilt test done.Now I am waiting for the result of Holter monitoring.After this i ll get headup tilt test done. Pls suggest me what can be the problem and possible solutions.Is the problem serious?