Thanks for writing your query.
After reading your post, it seems that you might have suffered from upper respiratory tract
You should take an antihistamine like Cetrizine 10 mg once daily along with a decongestant like phenylephrine
Warm saline gargles will help in relief of any throat congestion
Dry cough can be due to throat irritation
as a result of reflux of acid upwards as seen in Gastro Esophageal Reflux Disease(GERD) which can also result in gastritis. Your doctor might be thinking to rule out GERD as a cause of your dry cough.
Avoid cold/sour/spicy foods.
If the problem persists, get yourself clinically examined by an ENT specialist
I hope this is helpful to you.