Foldable multifunctional back cushion

The foldable multifunctional back cushion comprises a first back cushion body, a second back cushion body and a headrest, fixing blocks are arranged in the middles of the sides, close to each other, of the first back cushion body and the second back cushion body, a rotating mechanism is arranged between the opposite surfaces of the fixing blocks, and the rotating mechanism comprises a fixing column and a rotating rod. The fixing column is located between the opposite surfaces of the fixing blocks and penetrates through one end of the rotating rod, a positioning column is arranged at the other end of the rotating rod, the outer side of one end of the fixing column is sleeved with a fixing cylinder and a spring, a sliding cylinder is arranged on the side face of one end of the rotating rod, and clamping grooves are formed in the inner surfaces of the fixing blocks; the first back cushion and the second back cushion are rotationally connected, the angle position of the first back cushion and the angle position o