According to the Center for Disease Control and Prevention (CDC), Covid-19 symptoms vary greatly from person to person. Sore throat may be one of these symptoms. However, it is not known at which stage of the disease sore throat emerges.
Sore throat is a symptom present in many respiratory tract diseases. Flu is one of them, and often associated by an early sore throat. Since viruses usually enter through the nose and mouth, they first settle in that area, and cause a sore throat.
However, in research studies conducted with Covid-19 patients, sore throat was not very common. In a study with 55,000 subjects, the rate of sore throat was 13.9%.
Reference:
https://www.healthline.com/health/sore-throat-coronavirus#sore-throat-symptom