I have had bad costochondritis in the past. I also have a muscle that twists no and it looks like one of my ribs moves out of place. If I get too tired, I get the chest pains and the ribs feel like they are breaking.
One thing that you mentioned is that you were recently sick. If your dr. has not examined you for the chest pain since then, I strongly urge you to go back and have him check you out to make sure you do not have any heart problems. (sometimes I have heard of people getting an infection in the sac around the heart after an infection.) I know that could seem to be expensive to go and it be negative but it is so important to rule that out before you try to treat from home. It is better to play it safe when it is pain around your heart that causes shortness of breath.
Costo does cause your chest to hurt with each breath, but again, please be safe!