Hi I Have An Array Of Neurological Conditions Such As

Hi i have an array of neurological conditions such as dystonia, SBO, syringomeylia, etc. I have dyshagia. barium swallow test revealed marsh mallow get stuck in the middle of the chest and wouldn't move even with liquid. Swallowing liquid is fine. I have had gastroscopy which is normal but awaiting biopsies. I have lost a lot of wegight and they are considering PEG feeding tube. What do you think is causing the dyshagia and why is the blockage showing up on barium and not on gastrocopy? Many thanks Liam