Yeah it is the middle, I might try the laying side raises.
I dont do shoulders untill at least 2-3 days after chest(with heavy shoulder press), or I will do em same day as a lite finishing exercise to my chest ( No shoulder press just raise's).
even the front needs work, I was trying to do em twice a week quite a while ago but I was just making em to sore to Bench heavy at the end of the week.
I thort I might buy some gridiron shoulder pads and just wear those instead.