Severe Neck Pain After Sleeping

I woke up yesterday morning with a pain in my neck, like I had been sleeping with my head at an odd angle maybe. Some pain throughout the day when I turned etc., but nothing major.

Then today I woke in the early hours in agony. Couldn't support the weight of my head as the pain was too much and couldn't move my head more than an inch in any direction. Also moving my right arm caused stabbing pains in my neck.

I never sleep using a pillow - always flat, and I think this is the cause. I used a pillow and when I woke later the pain was much better, but still there - whenever I turn.

It's right where my right shoulder joins my neck.

Are there any exercises that would help this? I have had a hot bath and a shower with it on the massage setting but nothing made it better.

I have had this before after sleeping, that has gone away after a few days but the pain has never been as bad as this morning.

Any suggestions on speeding up a recovery? I don't want to be in agone all week.

Guessing it's a pulled muscle or trapped nerve or something.

Thanks