Thank you for submitting your question. You may have a condition called costochondritis- inflammation of the joints in the ribcage.
Pain associated with deep breathing(pleuritic chest pain) is usually caused by injury to the ribcage or the lining of the lung. If there is a problem with the lining of the lung, typically patients have shortness of breath. The pain should stay on one side only. Lying on the injured side should not produce any pain
In costochondritis, however, the inflammation can involve joints on both sides of the ribcage. Ribcage expansion(deep breathing) or pressing on the ribcage can cause pain.
Costochondritis is quite common among women. The cause is unknown.
You can try taking over-the-counter anti-inflammatory like motrin 200mg three times a day(be sure to take with food). You should see an improvement within days. If the pain does not improve, or if you develop any shortness of breath or cough, then you should seek medical attention immediately.
I hope this is helpful to you.
Most likely not heart-related. If leaning on the chest wall produces the pain, then it is almost certainly a problem with the ribcage and underlying muscles.
Pain related to heart disease is usually exercise-related, and is a pressure-like sensation. Cardiac chest pain is not related to the motion of breathing.
I doubt you have major lung problems. If so, you should have shortness of breath or cough.
The cause of costochondritis is unknown, although some people suggest that it is stress-related. Try motrin for one week and see how you feel. If the pain doesn't get better, the next step is a chest xray.