Dear doctor, how can pleura thickening cause pain if it originates on the visceral layer which isn't sensitive to pain?

Pleural innervation: It's true that the visceral layer of pleura has no sensory innervation. But the other layer of pleura -- the parietal pleura -- is continuous with the visceral one and lines the inside of the chest. This parietal pleura is richly innervated via intercostal and phrenic nerves, and is very painful when injured or inflamed. Ask anyone who's been awake while receiving a chest tube.

Parietal layer: Pleural thickening can occur in the visceral or parietal layers. The parietal layer is sensitive to pain. Visceral thickening can also result in inflammation of the parietal layer resulting in pain.