I have a feel like frequent dizziness fr past 5 days.its like a sudden dizzy feel wen shifting a position or working.and goes off.i ve sinus nd gerd

Many causes of: dizziness and light headedness. Sinus problems can in themselves cause dizziness. You need a doctor to help you sort this out. In general GERD does not cause diziness. You might need some xray testing or your brain but I usually say to patients if they want to do a brain CT they should do an MRI instead which is no ionizing radiation and more sensitive and specific for causes of dizziness.