Have you tried the Arthur Fonzarelli? You can buy the Yoga blocks and strap in a package at Wal-Mart for $11.00 or so.
You can also do the hip strap press and pillow squeezes in the 90-[90 position.
Okay, here are 6 more shoulder exercises:
While your in 90-90 on your back do:
1) "STATIC BACK PULLOVERS" (Do a Google search)
2) "STANDING SIDE BEND" (Right side stretch)
a) Back up against a wall.
b) Feet are shoulder width apart.
c) Reach your right arm overhead.
d) Side bend to the left.
e) IMPORTANT STEP: Shift hips to the right as you press off the ground with your right leg. This will give a good stretch of your hips and entire side of your body.
f) Repeat a-e) for the left side.
3) STRAIGHT ARM at the WALL. Please bear with me, it's worth the effort!
a) Stand facing the wall.
b) Straighten your left arm horizontally, or slight above horizontal, out to the side.
c) Put the pinkie side of your left hand (edge) against the wall so your thumb is pointing AWAY from the wall or downwards towards the floor. Rotation comes form the shoulder, not through the arm.
- If you can't get this rotation, lift your arm so it is higher than your shoulder.
d) Press the palm of your RIGHT hand against the wall like a pushup position. Use this force to rotate your chest and stretch your left pectoral muscles.
- IMPORTANT: Keep your shoulders and hips pointed in the same direction.
- Don't let your torso twist.
e) Let your left shoulder drop BACK and DOWN.
f) As your shoulder relaxes, rotate your torso further to increase the stretch in your shoulder.
g) Repeat for the other arm.
4) "WALL SHOULDER PRESS" (Do a Google search)
- It's the one where your back is to the wall.
- Arms against the wall like a scarecrow.
- Raise them over head while keeping arms against the wall.
- If this is too difficult, try it in your 90-90 position first.
5) "STRETCH PUSHUPS"
a) Standard pushup but put Yoga blocks under each hand.
- Elbows should be at your sides.
b) Allow the force of your hands to push your shoulders back before lifting your chest off the ground.
6) "SHOULDER DIPS"
a) Sit on the second from bottom steps on a staircase.
b) Lift your hands up behind you and place them on the third step.
c) Lift your body up and down by bend and straight your elbows / arms.