Hi..i Have Been Having Sternum Pain Since 5 Months. In

hi..i have been having sternum pain since 5 months. in addition to it have pain in the left side of my chest (front and back) i also have pain under left arm pit and left elbow.. i had an Ekg , chest xray done and my heart seems to be working fine.. i have shortness of breath as well. can costochondritis cause all these symptoms.