I think its may be your baby handling one said so you're abnormal posture will create one said muscle will work more pain produce .otherwise you check you're pain more present in neck ,shoulder ,
Next Steps
Firstly you go physiotherapy and you mainly take advanced myotherapy treatment and after that you leran that ergonomics advise for baby handling methods .....
Health Tips
Pain is a not real problem in you're body pain is a indicates forther problem s.........keep you're body your health .....