well, i dont have extensive orthopedic knowledge but it could be something like thoracic paraspinal muscle tension. simply put, there are small muscles along the thoracic spine that can get pulled or stretched or sore or whatever. this problem could have originated from a fall or a strain or something similar. pain on inspiration could be because the muscle is tight or spasming. of course pain there can mimic all kinds of conditions like kidney stones, or angina (cardiac pain, which you should not really be at risk for), or abdominal pain from any number of causes.
if RICE tends to take care of it, then its probably muscular in nature.
i also want to add that the internet (not just newschoolers but places like WebMD) is a great educational tool for your own health concerns, but its CERTAINLY not a replacement for a doctor. if you ever have a problem, or something just doesnt feel right....SEE A DOCTOR. there is no replacing a practitioners evaluation, or your good health.
sorry to ignore your bump before