It could be, and likely is both his gut and his cranial bones. This is what many people miss. It’s not just one thing. I would definitely seek out an experienced craniosacral therapist or a doctor of osteopathy to be sure. Depending on your child’s age and his symptoms, (which I don’t know) it should be checked out. It would depend on the craniosacral therapist ,but an osteopath would have a bit more education on craniosyntosis.