Some of the yoga poses:
For dorsal back:
1. paschim namaskarasana
2. parsva uttanasana in the above pose
For mid back:
1. gomukhasana
For shoulders:
1. adho mukha vriksasana (hand stand)
2. pincha mayurasana (elbow stand)
Note: the shoulder exercises I posted above can seriously injure you if you do not have the strength to do it, so typically you should be able to do many reps of surya namaskara, trikonasana, parsva konasana, veer bhadrasana before attempting it