I joined a choir when I moved to the country three and a half years ago. I don’t think of myself as a singer. I don’t sing in the shower. I don’t remember lyrics or which band recorded what album. However, I love music.
Now I’ve discovered that when I’m carried along on the wings of my choir, I can sing. I’m probably not going to do any solos soon, and I still don’t sing in the shower, but with our regular weekly choir practice, I’ve become better. And, it’s a joy to join with people to create harmony.
The choir director lets me lead some yoga stretches at the beginning of the session, and the group follows along as I demonstrate and instruct.
I try to think about what will prepare us best for singing, so we do movements that open up the lungs, loosen the rib cage and release tension from shoulders. I can hear audible sighs of relief when choir members let go of shoulder tightness, whether it’s come from physical work or stress.
Most of the choir members are not yogis, and they often come to our practice dressed in their work clothes, so we don’t do any complicated poses.
However, if you are a more experienced practitioner, here’s a program that you can follow to keep your lungs in good shape and help you address upper back and shoulder tension:

First, get centred in Tadasana
Then, do Adho Mukha Svanasana, hands on blocks
Followed by some standing poses:
Trikonasana
Uttanasana, hands on blocks
Virabhadrasana 1
Padangusthasana, concave back
Parvritta Trikonasana, with block
Pincha Mayurasana , with belt and block, for stretching and strengthening shoulders:

Pincha Mayurasana

Backbends:
Ustrasana
Lying supine, shoulder blades over foam wedge, Urdhva Hastasana
Urdhva Dhanurasana, blocks and belt

Urdhva Dhanurasana

A twist:
Bharadavajasana, seated on folded blanket
Inversions:
Sirsasana, using blocks at the wall
Sarvangasana, supported on bolster, sacrum on chair
Halasana, legs supported on bolster on chair
Forward stretch:
Janu Sirsasana, with hands on blocks
And finally, breathing and relaxation
Ujjayi pranayama, lying with shoulder blades supported
Savasana