Tai chi. I was plagued with neck pain during and after cycling. I had suffered a compression injury years before and just thought time and degeneration had caught up with me and that was my lot.
A friend suggested tai chi. I was sceptical and reserved and felt a bit of a berk at first waving my arms around etc, but the improvement was pretty quick so that gave me impetus to continue.
It work for me by increasing my awareness of how my movements were executed ie, I learned to feel which muscles did what and concentrate on the signals the joint and muscle were sending to my brain during a limb movement. I realised that most of the time my neck and shoulders were in tension and this could be relieved by measured and mindful gentle movements.