Chest pain?

Chest pain on right side when i cough and sometimes when i breathe in deep or turn my back. Chest pain near my sternum when i fully exhale or press with my fingers (not touch - i mean press a little). Last but not least I sometimes get pain in my chest on the left side (can be upper chest/lower chest, pain can "come and go"). It doesn't seem effort related. I have had simptoms like this since june. Cardiologist sais my heart is ok. (2 ekgs and 2 cardiologists). Blood tests normal - just a small lack in calcium. I have some problems with my thoracic spine (a lot of time at the office) and some back pain/arm. I had a mild pneumonia in august..(treated that one :) ). Still i don't know what to say about my pain. Any ideas? I'm 22 years old. I'm fit and athletic. I don't smoke and I'm fairly active. Any ideas? I intend to do an abdominal echography after this short holiday. Still...i would really appreciate your help.