What are your other symptoms? Cough? Congestion? Shortness of breath? Fever?
Whatever your symptoms are...go to a Dr. It could be something as simple as pleursy that some NSAID's would clear up. Whatever...a simple chest x-ray will clear up the pneumonia issue.
What's the point in going to the Dr. if you think you have pneumonia? Hmmmm....let me think....oh, yeah, people STILL die from untreated (and treated) pneumonia....it isn't a disease of the "olden ages" that people USE to succumb to. It still happens every single day.
Just go to the frickin' Dr........mmmmkay? Trust me, I'm a nurse.
Good luck.