There are a couple of reasons this could be happening. If your baby is crying and arching their back during a feeding then it could be that they have either acid re flux, or gas. The pain from both of these is enough to make you try to get away from the pain by arching your back. Another reasons could be that the milk just isn’t coming out at the pace they desire it to, this can be frustrating for the baby. Another one, is allergies, if the milk is making them gassy, this could be another cause for concern.

Key Takeaways:

• Arching the back is a symptom of acid reflux which can result in stomach problems and vomiting.
• Babies tend to arch their back when they’re angry that they’re not getting breast milk at the pace that they want.
• Changing positions can make a huge difference and help your baby feed. Feed your baby in a semiupright position and use a breast pump if needed.

“Despite the benefits of breastfeeding, some mothers encounter problems at feeding time, and a fussy, squirmy baby is among the most common.”

Read more: https://www.hellomotherhood.com/article/555380-my-baby-is-crying-arching-his-back-when-breastfeeding/