It hurts to breath...?

For about 3 months I've noticed that I don't breath fully. I take little breaths. I'm not doing it on purpose as I feel my ling squueze so I only take little breaths. At first I thought it was because my chest is heavy.. 42 DD... But they've been thst size for awhile.. For the past week I've had a little cough... I don't have a cold or anything but when I cough it's dry and the back if my lungs hurt... The top part if my back hurts to now... Is this something serious??