OP has made an exact description of my recent injury. I don't even know how I did it, but I spend my days moving pianos, so there might be a connection. I hurt myself a couple of months ago, and the best comparison is that it was like having sciatica, but in the arm not the leg.
First couple of days I couldn't pick up anything heavy with my left hand, and like the OP I couldn't find many sleeping positions that weren't painful. Bike riding was out, because the position (arms extended, head tipped back) lit my arm on fire, but I didn't miss a day of piano moving.
When you are my age (65) every injury is a potential career ender. A couple of weeks into it I tried to go on a MTB ride, but turned around after a couple of miles. I wondered whether I would ride again. I thought about chiropractic, but never went through with it.
Even though it was painful, I still rode my town bike short distances to monitor my progress. Gradually the pain subsided and I could ride for real. Now I get a little tingle in my fingertips for a minute or so when I jump on the bike, but it goes away quickly.
I don't have any medical advice, but if my experience is a guide, it will eventually go away and you will have to regain your bike fitness.