Im scared.. symptoms of pneumonia?

I have had a cough with flem or however you spell it these past 3 days. Yesterday i started feeling more tired lthan I usually am after school. Today, I have pain in the middle lower part of my ribs..?idk but when i cough it hurts really bad, so I try not to cough too hard. Should I wait 3-4 days to see if the pain goes away? if it doesn't, i'll go see my doctor. What do you think? is this pneumonia? (the middle lower part of my rib also hurts whenn i bend down)