Why does music sound off key all of a sudden?

Those who develop diplacusis usually notice it suddenly after exposure to loud noise, a bout with an ear infection or trauma to the head. As you can imagine, musicians notice this condition more readily than non-musicians as their ears are more sensitive to pitch and tone.

Why do things sound different when I’m sick?

Sometimes a cold virus causes a buildup of fluid in the middle ear, making it difficult for sounds to travel efficiently from the outer ear to the eardrum. Individuals may notice a clicking sound in their ear, or that conversations and noises are muffled.