Place your left hand on to your right shoulder and feel around for the top of the shoulder blade.
Feel around for any areas where you can find tension. The Levator Scapula can sometimes fell like you are flicking over the muscle.
Either using your fingers, or a massage ball, roll around that area. When you find a tender spot, hold on that area and move the head around from side to side and forwards and back.
Work on the area for 3-5 mins. Repeat on the opposite side.