Help! could sore ribs cause breathlessness?

Yes: People with sore ribs typically won't take the usual number of deep breaths or big sighs in a given time period (say per hour) that we all usually unconsciously do. This is called 'splinting' in medical lingo, and can lead to shortness of breath. Rib stuff is hard; you simply have to deal with the discomfort until they heal up. If you are having significant breathlessness, go get an xray.