Question: what are the main causes of a sore throat?
Answer: Colds, the flu, and other viral infections. Viruses cause about 90 percent of sore throats ( 2 ). ... 
Strep throat and other bacterial infections. ... 
Allergies. ... 
Dry air. ... 
Smoke, chemicals, and other irritants. ... 
Injury. ... 
Gastroesophageal reflux disease (GERD) ... 
Tumor.