Hi I Have This Back Pain.. Right In The Middle

Hi I have this back pain.. Right in the middle of my back, not lower not higher but bang on the middle I get it when I stretch, there's this little pain and when I bend down it hurts in that same spot.. Like it hurts to move that part the pain is bareable but there's that little pain.. Middle back but a tad bit to the right and that's it there.. Why could tht be?