What Could Be Causing Back Pain On The Left Side I Have A Pain In My Back On The Left Side Behind The Middle Of My Ribs. What Could Be Causing It?

I have a pain in my back on the left side behind the middle of my ribs. What could be causing it? - what could be causing back pain on the left side

It hurts very badly and when I straighten it or to sit in a way that is easy to try, I feel a pain in the ribs on both sides. No idea what could be the cause, or if you?

Thank you.