elaine, your husband is a romantic.
Pretty much all mammals have C6 and C7 vertebra. Less the 1% of humans have and extra rib at that level.
https://samarpanphysioclinic.com/cervical-rib/
Advancing scoliosis increases the torque or upper body twist. If low body scoliosis is to the left the upper body rotation will be to the right. Increased rotation may have made you aware of that previously untroublesome extra rib.
What will you do for the pain.