Levator Scapulae is situated at the back of your neck, it originates at the first four cervical vertebrae and attaches on to the medial angle of the scapula. At the top it lies under the sternocleidomastoid but most of it is deep to the large trapezius muscle.
As its name suggests it's primary action is to elevate the scapula. It's involved, along with the upper traps, in lateral flexion (unilaterally) and extension (bilaterally) of the neck. It also acts to stabilise the scapula.