PCOS,and vertigo may be related if there is no other cause,but sinusitis is totally different disease
Sinusitis is an infection ,may be due to these ur frnd can feel such symptoms.
Do not take cold water,avoid sunheat, try to avoid too much temperature changes,gurgle with luke warm water,take vapour of warm water.
Next Steps
Take-
1.Bell 200-2 drops Thrice a day for 3 days.
2 .Nat Sulph. 6X-4 tab thrice a day for 10 days.
report me after that.