Will a sore throat affect my athletic performance?

It might. If you're ill, your body is using resources to fight off the infection. This may affect the rest of your body.

Depending on the cause, it may or it may not. If infectious specifically it will influence athletic performance due to potential fever and generalized muscle pain, not as much if symptoms are rather chronic, due to allergies for example.

MANY OR MOST ATHLETIC PERFORMANCES REQUIRE CONTROLLED BREATHING OR USE OF VOICE. A SORE THROAT WILL CAUSE SOME DISCOMFORT OR PAIN BUT A TRUE WARRIOR WILL PREVAIL. NO PAIN ,NO GAIN.

A sore throat is usually an indication of infection and will have systemic effects that have the potential to affect athletic performance.