I had something similar many years ago and was finally diagnosed with Bornholm Disease. My pain was severe and seemed to affect the nerves between my ribs on one side. You might like to read up on that and see if it sounds like what you have.

"Symptoms may include fever and headache, but the distinguishing characteristic of this disease is attacks of severe pain in the lower chest, often on one side.The slightest movement of the rib cage causes a sharp increase of pain, which makes it very difficult to breathe, and an attack is therefore quite a frightening experience, although it generally passes off before any actual harm occurs. The attacks are unpredictable and strike "out of the blue" with a feeling like an iron grip around the rib cage....." http://en.wikipedia.org/wiki/Bornholm_disease