I had pain like that twice....once the doctor said I had a cracked rib? (nothing they could do but told me I could wrap it and apply heat) And other time it was some sort of lung infection? (was given antibiotics) It was in the same location like you are having it.
I remember when I was pregnant, I had pain right between my ribs and the doctor said that was just the baby...I guess Katelyn was pulling on my ribs (ha)
Hope you feel better soon!