I'm 25 Years Old And Currently Living In Taipei, Taiwan.

Question: I'm 25 years old and currently living in Taipei, Taiwan. Recently I had a chest X-ray as part of my health checkup to apply for my residence card and work permit, and the doctors said I passed, however they gave me a slip of paper that said they found "bilateral pleural thickness with lung fibrotic change". They said this may be caused by overlapping soft tissue/rib shadow, scar from previous infection or others, and suggested I visit a chest clinic 3 months later to see if it changes. I'm not quite sure what this means, and the doctors here don't speak English as a first language, so I'd like to consult a native English speaking doctor so I know exactly what this is, because it sounds concerning. I was hoping you could help elaborate on what this is and what it might mean, because the terms used don't make much sense to me. Thank you.