text: my ribs hurt wit even my arm on them and i did notthing to them why? i did nothing to make them hurt and i get sharp pains right under the left rib sometimes too did you ever injure yourself in the ribcage? are you thin and smoke? torn muscles between the ribs will cause pain for years. if you are thin and smoke, you may have what is known as "friction rub". it's when the lining of your lungs rub agains the walls of your chest cavity. see a doctor soon.