I am feeling tightness in my upper left side of my chest above the breast . Sometimes it feels like a balloon is filling up in my chest. I went to ER and they kept me over night to test my heart ( EKG , blood test , and stress test). All tests came back normal and was released. But, the pain is still there. I feel the pain when I am sitting up in a chair, but not as much when lying down. Pain medications do not help the problem or even mask the pain. Any ideas? I am a male age 42.