Pedi says my 6 month has heartburn. she wakes often crying, even when held she squirms and cries. nursing helps soothe her. what else could it be?

Reflux: It could be reflux esophagitis or heartburn as your pedi says. It could also be a kind of food intolerance or allergy. For breastfeeding babies removing milk and other dairy from the mother's diet sometimes helps. If this is a new problem and the baby's stool has become loose/runny it could be an infection. If the stools are very firm, pasty or hard then treat for constipation.

? Teething: While reflux could be one of the causes i wonder if it is from teething since she is comforted with feeding.