A Cold
It happens thanks to a virus that causes a runny nose, sneezing, and sometimes fever. It may irritate your lungs and airway and bring a cough that can make it hard to breathe. There’s no cure, but it usually gets better on its own in a week or so. See your doctor if you have a fever higher than 102 F, if you’re wheezing, or if it’s hard to catch your breath.
Pneumonia
A virus, bacteria, or fungus infects the air sacs inside your lungs. Then those sacs fill with fluid. This makes it harder to breathe. You also could have chills and fever, and you might cough up a thick, colored mucus. Check in regularly with your doctor. They might prescribe antibiotics if your pneumonia is caused by bacteria. Other types are harder to treat, but rest, fluids, and over-the-counter meds can make you feel better.