Hello..sometimes I Have Short Sharp Pane In My Middle Back..it

hello..sometimes i have short sharp pane in my middle back..it comes and goes in second..it is when i do certain movements like when i slip suddenly and try to hold my balance then i have that sharp pain..sometimes during night when i turn in bed from side to side..i noticed 3 dark spots on my spine around the area where the sharp pain comes and goes...could it be something serious?