What Causes Abdominal Pain And Nausea?

I am three years into breast cancer treatment taking femara. Did not do chemo or radiation, double mastectomy. Taking acid reflux meds. I am having some pain in my stomach, nausea, no fever, I have a pain that began behind my left ear. It began hurting down the left side of my neck and when I bend over I terrible sharp pain goes through the left side of my chest. I can lift my arm above my head and do not seem to have any problem with rotating my arm.