What is going on with my baby? Can't transfer milk and muscle tension.

My daughter is eight weeks old, and we have had trouble breastfeeding since she was born. She was breech and delivered via C-section. On our second night in the hospital, she began refusing the breast and acting frustrated when we tried to latch her. The lactation consultant said that when she did latch, we had a good latch and everything looked great. They chalked it up to her being frustrated because she couldn’t quite figure it out yet and sent us home.

About a week later, we were still having a lot of trouble, and I suspected she wasn’t transferring much, which I confirmed with a weighted feed. We got in touch with a new lactation consultant who came to our home, and she suggested that I might have low supply. During this time, I also noticed that the baby seemed to be chomping more than sucking. This is my second baby, so I have some idea of what a correct latch should feel like, and this didn’t feel right. I also noticed that she had a hard time fully opening her mouth when rooting. 

We chalked this up to low supply, and I began pumping and triple feeding to increase my supply. After a while, this became overwhelming, and we moved to mostly pumping but still tried to latch once a day.

When bottle-feeding, the baby still had trouble getting the milk out. We used the Philips Avent Pace Feeding bottles and had to bump up to Flow Level 4, which is typically for babies 3+ months. However, she seemed to chomp at the nipple and struggled there as well.

She can suck but only for a few minutes before she gets too tired to continue.

After increasing my supply sufficiently and still having trouble, I decided to contact a third lactation consultant. We saw her last week, and she suggested that my baby needed a good stretch and that her shoulders were towards her ears. She mentioned that my baby was having trouble activating her tongue because her shoulders were so tense and suggested we visit a craniosacral therapist. We visited one today, and the therapist noted that the baby was tense all over. She was squirming and crying at the gentlest of touches, especially in her shoulders, arms, and pecs. 

The therapist also noted she was tense in and around her mouth and that when resting, her tongue was at the bottom of her mouth instead of pressed against the roof like it should be. Additionally, she mentioned that her palate is slightly high. All three lactation consultants we’ve seen have not noticed any tongue or lip ties. However, the craniosacral therapist suggested there could still be a posterior tie that’s hard to spot.

We also have an appointment coming up next week to see a pediatric chiropractor, from whom I hope to get more information.

Does anyone have experience with this inability to suck mixed with muscle tension? Is the tension caused the latch problem or maybe the latch problems are causing the tension and there's something else going on?

I have read that some folks will see an occupational therapist for feeding issues. I have looked into this, and there seem to be none in my area that work on this sort of issue. We are in Lancaster, Pennsylvania.