Hi, I can't tell you what it is, but I get somethign similar once in a while. Mine only happens when waking in the morning, laying on my side. I'll be laying there and breath in, and get an almost sharp pain inside my spine the deeper I breathe in. Then the pain radiates out to the side a little in that small area. It's happened to me in my thoracic spine and also in my lurabar spine and usually happens while on my right side. I do not get any chest pain nor pain in my lungs when it happens, I only get the pain coming from what feels like in my spine somewhere. Once I get up out of bed and for the rest of the day, it doesnt happen. And mine doesnt happen constantly. Does your pain feel like its coming from the spine or does it seem farther away to the side? And does it hurt your lungs at all taking deep breaths? I certainly cant guess what it could be, but you should probably see a doctor to have it checked out. Maybe it could be something spine related, but maybe not.