If we talk about area under the ribs then that should refer to the stomach and down and that would refer to quite a long list of condition that would cause pain under the ribs but there is one part of the body that might be overlook by others. That is the Diaphragm. The Diaphragm is actually a thin muscle that separates the chest from the stomach. It is actually attached to the lowest rib all the way around.
It is the trigger points in the diaphragm that cause pain under the ribs and it often happens when you exhale. This trigger points in the muscles give you a sense of shortness of breath. Pain in the ribs is sometimes mistaken for costochondritis or inflammation of the ribs or you may be diagnose to have gallbladder problem, ulcers or gastroesophageal reflux (David G. Simons, Frozen Shoulder Workbook, page 187).
What are the causes of pain under the ribs? Overexertion, chest breathing, chronic cough and emotional distress can cause trigger points on the diaphragm as well as hunched posture and or any other condition that makes you struggle for breath. For those people who are quite conscious with their body figure and tends to keep their stomach in all the time, this might cause pain under the ribs for you are affecting the natural way of breathing.
How do you treat such condition? You can do some self treatment for those trigger points of diaphragm that you can access. Simply dig under your ribs with your fingers and do a deep massage as you can. Do it twelve times each trigger points as much as possible. The area can be access easily if you exhale and pull your stomach in, this is beneficial when done with the massage.
If pain still persist over a period of time despite the self care treatment then it is time to consult your health care provider to remove any other serious condition that might cause the pain.