Hi I am 19, I get this really bad back pain, it keeps coming and going. I can only describe it as excruciating. It's the upper and middle back behind my lungs. Its very painful breathing in, when I breath in its such a sharp pain it makes me stop and breath out again. I really don't know what it is. Has any one else experienced this and do you know what it is?

You need to go to the doctor.
I know I was having the same problem and thought it was bronchitis but it turned into walking pnemonia.
Whatever it is it is serious enough to go to the doctors.

I am sorry for you. It is you twist your rib and It hurts. Just move in a position and it will pop back into place. It happens because you might have weak ribs. (I do) (it happens to me)