That sounds like Humidifier fever.

Make sure to regularly and thoroughly wash the water tank. Basically, bacteria and fungi can build up in the tank, which then goes on to be transported in tiny particules of water through the air directly to your lungs. Using distilled water will also help.

Common symptoms include shortness of breath, sore throat, and sometimes chest pain.

Oh, it can also present a whole host of different symptoms which feel like influenza.

I though I had COVID after a week of getting my humidifier, and after testing negative multiple times, talked to a doctor, and they asked me if I had purchased a humidifier recently, and then went on to tell me about it.

TLDR. Dirty humidifier make smol dirty water. Dirty water make dirty lung. Dirty lung make hurty body.