Hope you only have a temporary muscle problem and nothing more.
Couple of years ago after a long overnight flight back from honeymoon, all of a sudden I couldn't move the day after and had to roll everywhere! Turns out I had trapped a muscle at the top of my rib cage from the many hours of sitting in a rigid position.
GP was restricted in what he could do, made me a physico appointment but I couldn't wait a week feeling like that. I rang up a sports physio and got an appointment that day, he cracked some bones, forced me to do certain stretches, it made it worse for a few hours then it started healing. Best £27 I had spent in a long, long time.
Hope it's something simple like this and all the best.
PS. Yes I rang to cancel the NHS physio afterwards