There are a couple you could add. The first is simply upright rows using a barbell. Grab the bar close together with an overhand grip and literally pull the bar up to you chin/face. This works the front and side deltoids as well as the trapezius at the top of your back. However, these muscles are also hit by your pressing/side raises and shrugs.

The other is for the rear deltoid which will only get hit with your back workout. A couple of ways of hitting them.

Be careful of the back again though.

Grab a couple of light dumbbells and bend over so you are just above parallel witrh the floor. Starting with the dumbbells hanging straight down raise them in an arc out to the sides with a slight bend in the arm.

You can also do these propped against an incline bench to take the stress off the lower back.

The other is to use a cable cross over machine (does your gym have one?) or any machine with a cable attachment at the top. You do these one arm at a time. stand at 90 degrees to the machine so the handle is over your right shoulder. Reach across your body with your left hand and grab the handle. Now keeping your arm straightish pull the handle back across your body and out to the side. Its the same movement as above with the dumbbells except you are standing up.

THe other could be for your lower back to try and strengthen it. Deadlifts might be too much so hyper extension may work - see below