The focus of investigation.

The cervical spine.
(web image)

There's much to learn about how the human body works but, when it's working properly, there's little inclination to ponder. And when it's not working properly, the complexity is almost overwhelming. Some have suggested that Ben's problem might be in his head but that's not true*. The problem is below the head and above the shoulders where there's an amazing collection of highly important bones, nerves and muscles:
Spinal nerve C1 ... provides motor innervation to muscles at the base of the skull. C2 and C3 form many of the nerves of the neck, providing both sensory and motor control. These include the greater occipital nerve which provides sensation to the back of the head, the lesser occipital nerve which provides sensation to the area behind the ears... The phrenic nerve arises from nerve roots C3, C4 and C5. It innervates the diaphragm, enabling breathing.  (Wikipedia)

Symptoms of problems in this area include headaches, migraine, neck and shoulder pain, muscle spasms, allergies and asthma. All of those sound very familiar. The focus of the next investigation is a possible "developmental problem" in C2, axis. "Developmental problem" is a term that we've encountered before, twice in fact.

* I did ask if the recent MRI of the head showed any large empty spaces but was told there's a perfectly formed brain in there.