Answer:
Costrochondritis, inflammation of the cartilidge that connects the ribs to the sternum, is my first thought. I am happy to hear that you went to your doctor first and ruled out some possible serious causes. Go to the link I have as my source for more about costrochondritis.
You may want to go to another doctor, so you have more than one opinion. It could be anything, from heart problems/angina problems, or it could be panic attacks/anxiety. You also could have pulled something somehow, or hit something.
Does the pain get worse when you breath in deeply? If so it might be costochondritis: http://www.emedicinehealth.com/costochon...
I had it once and it took about a month to heal.
Or it could be a separated rib, but that should show up in an x-ray. If your doc didn't give you a diagnosis, you may want to get a 2nd opinion.
it could be caused by stress if you've been really stressed lately you should take it easy..
It sounds like condyll costeritis, forgive the spelling, however, if you are not satisfied with your Dr.s diagnosis, see another one. Good Luck!!
I sometimes get sharp pains when I eat or directly after. They aren't really painful but just a nuscience