Hi,
As a breastfeeding mother , you may have tendency to lean forward looking at your child. To have that touch , you can hold the hands of your child for motherly touch but don't bend or look downward. This may develop bad posture also straining your neck and back muscles.
You need to strengthen your muscles.
No need of using any belt.
Next Steps
You can contact me through Practo. I will teach you exercises through online consultation.