is blood under the skin in the soft tissue
most commonly as a result of an injury
. A blood clot is solidification of blood products blocking the veins or arteries. Bruises do not cause blood clots
in the vascular system. Your pain sounds pleuritic and their are many causes for this such as inflammation or infection in the lung or the lining of the lung and chest wall. Muscular strains in the chest can cause a similar pain. If this persist or you have any additional symptoms such as shortness of breath
or a productive cough I would seek medical attention.