Pleural effusion means extra fluid has built up in the space between your lungs and your chest wall. That space is normally paper-thin, so even a small amount of liquid can press on the lung and trigger clear, easy-to-notice symptoms. The most common complaint is a dull ache or tight feeling in the chest that gets worse when you take a deep breath, cough, or laugh. Many people notice they’re short of breath after walking up stairs or carrying groceries—activities they handled easily before. The shortness can feel like you can’t fully fill your lungs or like you’re breathing through... Learn more