A chill or shivering sensation felt in the body, typically from fever or the onset of illness. Also used for a chill down one's spine from fear.
風邪をひいてからずっと寒気がする。
I've been feeling chills ever since I caught a cold.
急に寒気がしてきたから、熱を測ってみよう。
I suddenly started feeling chills, so let me take my temperature.
その話を聞いて背中に寒気が走った。
Hearing that story sent a chill down my spine.