What Causes Painful Knot In The Back Near Spine?

HI DOCTOR, I'VE HAD THIS KNOT IN THE MY BACK NEAR MY SPINE ON THE LEFT SIDE. IT FEELS LIKE ITS BEHIND MY LUNG ALMOST FOR ABOUT THREE DAYS, ITS NOT SUPERFICIAL, IT ACTUALLY FEELS DEEP. I HAVE TRIED STRETCHING BUT WHEN I DO I HAVE A SEVERE SHOOTING PAIN FROM IT AND STRAIGHTEN UP AGAIN I GET EXTREMELY DIZZY AND MY LEGS GET SHAKY I LOOSE BALANCE AND MY VISION COMPLETELY BLURS OUT. ICE/COLD PATCHES AREN'T WORKING EITHER AND ITS UNCOMFORTABLE WHEN I BREATHE OR MOVE. IT HAS ME VERY WORRIED. I AM A 20 YEAR OLD FEMALE WITH NO SEVERELY ILLNESSES JUST MIGRAINES