I am having pain on my left side...shoulder, underarm and above my left breast. If I tilt my head back towards the left side I can feel pain or almost like pulling near the top of my breast. I can sometimes feel pain in my forearm to the elbow . I can feel soreness if I massage areas...I suffer from seasonal asthma and I smoke. I have post nasal drip that can also may cause little mucus. I am not really out of breath and I don t feel pain in my lungs nor have I coughed up any blood..my doctor says I may have injured my shoulder...I am scheduled for a mammogram ...could lung cancer cause pain? I do secretary work...and sometimes favor that side when talking on the phone...carrying shoulder bags. Also I have to constantly reach for the door buzzer. I am scared