Initially, you may experience cold-like symptoms like a runny nose, sneezing and a sore throat. Colds develop slowly, but influenza comes on suddenly. Colds are a nuisance; you feel much worse with the flu. Common signs and symptoms of the flu include a fever over 100, aching muscles, especially in your back, arms and legs. Chills and sweats, headache, dry cough, fatigue and weakness, nasal congestion.