I recovered from pneumonia but am now experiencing chest pain and breathing difficulties after exercising. can pneumonia cause permanent lung damage?

If bad, it can, but!: Some scarring can occur. But people with pneumonia rarely breath deeply, so some discomfort is not unusual. Significant inflammation may indicate a pleural reaction, so this needs to be considered. Start slow and expect improvement with time! what sporting activities you are engaging in is also a factor!

Occasionally: Usually the common pneumonias completely resolve. But you can get pneumonia again. And there are other causes of discomfort. See your pcp.