Coughing while lying down and not coughing while sitting may be caused by a variety of diseases such as heart failure, pneumonia or chronic pharyngitis. 1. Heart failure: heart failure patients lying down after the increase in the volume of return blood, aggravated pulmonary stasis can appear cough, so that the patient there is lying down on the cough, sitting on the performance of coughing. 2. Pneumonia: patients with pneumonia may aggravate the pressure in the lungs when lying down, which may stimulate the function of the lungs and cause the above performance. 3. Chronic pharyngitis: the existence of chronic pharyngitis when lying down on the cough is mostly due to the respiratory tract is not smooth caused by sitting is conducive to keep the gas smooth, usually there is no coughing symptoms. Lying down coughing sitting without coughing may also be caused by other reasons, the patient should go to the hospital in time to clarify the specific causes of the disease.