Based on the context and the answer, generate a question. 

Context: I woke up with body and stomach cramps and a mild temperature ... oh oh . So I basically ate nothing and spent the day in bed . It proved the right strategy because 24 hours later I was much improved ! In retrospect I had the virus for a couple of days and the muscle pains were part of what made the bed uncomfortable .

Answer:

They are suffering from a flu .



Why is the narrator potentially sore ?