Hi Dr, I am 54 yrs old. Earlier today i was laying down and I had chest pains in my chest. It is in the left side, about middle of chest. Feels like it is over my heart . When I lay on my left side, it hurts more than laying on my right side. I have noticed that when I inhale, it doesn t hurt. When I exhale, it hurts with every heart beat.And it has been steady all day long. What could it be? Thanks