Runny nose, sneezing, and headache are usually caused by a cold or an allergy, when the nose and sinuses become irritated. Take good rest, drink warm fluids, do steam inhalation, and avoid dust, smoke, or cold air to ease symptoms. Keep your head slightly raised and watch for signs such as fever or an increasing headache. A doctor may recommend treatment if it does not settle within a few days or worsens, so it is best to get checked.