Why does my right side of my chest and right back shoulder hurts?

Many causes: Its important to establish a diagnosis. Your pain could be from the shoulder or referred. Common referred sources include: abdomen, heart and neck. Shoulder sources include: arthritis, labral tears, instability, tendinitis, rotator cuff tears, bursitis, painful bony spurs etc. Therefore proper diagnosis is essential to stopping the pain. See an orthopedic surgeon. Good luck!