Hi Suzy.... welcome to OCF and so very sorry to read about your discomfort. Although scarring from a neck dissection has been a problem for many people it's not particularly so for me - but my neck is definitely tight and still largely numb on the surgery side, so I sympathize.
Have you tried a massage therapist/physical therapist? That can really help, as can some topical ointment rubbed into the neck daily. Even something you get at your local chemist (that's the word for pharmacy in the UK, right?) could be helpful.
I'm very encouraged to read that you were able to get back on solid foods so quickly! Took me months. But your swallowing difficulties lead me to wonder if you have either some esophogeal narrowing or something else going on down there that bears attention.
I had both, and have had my esophogus dilated maybe half a dozen times by a gastroenterologist. You might ask about this. Like you, I felt that food was continually getting stuck back there and I know the feeling is horrible. The dryness we all get after radiation doesn't help of course. Be sure and gargle with water and baking soda, that often helps. There are also sprays and such... I don't know much about them specifically, but you do certainly need to be on Biotene or other dry-mouth specific toothpaste if you're not already.
I also saw a swallow therapist and had some real-time radiation scanning that determined that the mechanism wasn't quite working correctly. The therapist gave me exercises to do and, over time, the problem was significantly reduced.
Time is a great healer as you know, and my guess is that most of what you're experiencing will improve. But I'd still recommend you speak with your docs about possible narrowing and/or other swallowing problems. And of course about what you can with the scarring issue.
Please keep us informed. My very best thoughts are with you.
David 2