Hey David,

Yes i had a similar experience. I physically crashed after a few months but eventually i bounced back. What you describe sounds very much as a neck problem. Some other members can give you good advise on that.

As for the nights where you cant fall asleep. Dont lay awake in your bed for approx 20 minutes. If you do get up, go drink a glas of water, sit in your sofa, or do something else that you find calming and then go back to bed when you are tired again.

It also sounds a bit like burn out. Not that it is burn out, it is injury related but the mechanism is very similar. Know that your threshold for stress and workload can be lower than before and it is easier to crash. It is good that you are working again so you can build up that threshold again. The general advise is to go back to activity as soon as someone can. Try to discuss with your workplace how much you can take and how much is too much. Your recovery comes first.
Good luck!