I am so sorry that you are experiencing these symptoms, Bill. You may have done so already, but have you contacted your movement disorder neurologist to assess your condition. As a Speech Pathologist [SLP], who has PD, it is recommended that an appointment be scheduled with an SLP who can assess your swallowing difficulty. They can work with you on safe swallowing techniques, as well as food consistency changes that will make it easier to swallow. For the pain in your back and neck, it is suggested that you make an appointment with a Physical Therapist to assess your neck/back issues and balance issues which are definitely related to the PD. Maybe, in the meantime, while waiting for a movement disorder neurologist appointment, you could request that your primary care doctor write a script for "Evaluation and treatment for physical and speech therapy for dysphagia" to help you. It is suggested that you see an SLP ASAP for the food getting stuck in your throat, which can be a contributing factor to your weight loss and aspiration, which is a very serious problem. Aspiration is the number 1 cause of death for people with PD.[1] I would get help sooner than later. Please keep me informed about your progress, I care.
[1] https://www.michaeljfox.org/news/swallowing-and-parkinsons-disease
Concerned because I care,
Best, Marc M., Moderator, SLP, parkinsonsdisease.net