I'm obviously not an expert, but I think it would be pretty unusual for you to be walking around that long with a PE and not know it. I went to the doctor a few months ago with similar symptoms, also convinced I had PE. She diagnosed me with a muscle strain that was causing the pain when I breathed in. It took quite a few weeks to clear up completely... maybe 6 or so? So that's definitely something that can cause long-lasting chest pain.