The pleura is the membrane that covers the lungs, according to InnerBody. The pleura consists of two layers, with the parietal pleura forming the membrane's outer layer and the visceral pleura forming the membrane's inner layer.
WebMD explains that the pleura provides protection and lubrication of the lungs' surface as the lungs expand and contract during inhalation and exhalation. Pleurisy, also called pleuritis, is a painful condition that occurs when the pleura becomes inflamed. The roughened surfaces of the pleura rub together causing pain during breathing, coughing and sneezing. Viral infection is the most common cause of pleurisy. Less common causes are systemic lupus erythematosus, cancer, liver diseases, rheumatoid arthritis, drug reactions and chest injuries