Have back pain from lifting patients and am looking for jobs in baby care. Any reason I cannot do that?

Lift correctly. Babies are lighter so maybe that will be okay but you still have to stretch over. Make sure you are using good mechanics when you lift and strengthen your back muscles t be sure.
Neonatal care. I have a friend who switched to nic u nursing after back surgery was a perfect fit for him the babies weigh just a few pounds lightest patients.