Feverish feeling!??

Sometimes at night I feel very ill even if I’m not. Like I legit will feel like I’m coming down with a flu or cold, I’ll feel like I have a fever, my body is warm, chills body aches all that. But I check my temp and it’s normal. And then the next day I wake up perfectly fine feeling, so idk why that happens. Anybody else? Right now Istg I feel sick like my back hurts and my skin is hot to the touch and my head hurts.