ailment
A minor sickness or physical problem that makes you uncomfortable.
An ailment is a physical problem or illness, usually something minor that makes you feel uncomfortable or unwell but isn't terribly serious. When you wake up with a sore throat, a stuffy nose, or an upset stomach, you have an ailment. A headache is an ailment. So is a sprained ankle or a rash that won't go away.
The word suggests something bothersome rather than dangerous. A cold is an ailment; pneumonia is a serious illness. A mild stomachache is an ailment; appendicitis requires emergency surgery. Doctors treat ailments every day: the aches, pains, and minor sicknesses that make people miserable but usually heal with time, rest, or simple medicine.
You might hear someone complain about their various ailments, especially older people describing their creaky knees or occasional backaches. The school nurse sees dozens of ailments each week, from scraped knees to headaches to mysterious tummy troubles that sometimes appear right before math tests.