As previously stated great your on a time limit.
By no means am I a doctor.
I have had similar pain before just didnt start as high up on me, but did work its way down my back. Turns out Had a disc pushing on my spinal cord.
Also could be inflamed nerves that are being pinch. Which iceing as mentioned above can help.
I like the "if not better by Friday." I am always pleased when someone decides on a "time limit," as it is proactive!
Here's something you can do in the meantime -- you know those Blue Ice Packs? Well.... when the SAME THING happened to me, I was told to "ICE" all throughout the day.
I said, "Well, how much? A couple times?"
The answer was No! Ice for 10 minutes EVERY 2 HOURS!
OMG THAT HELPED TREMENDOUSLY!!!!
Never underestimate the effectiveness of ice! It will reduce swelling which means it will reduce pressure, which means things will "relax all around" those millions of eency-teency little nerves everywhere.
Now, I'm not a medical doctor, a professional, or even an amateur, so I cannot give advice. Therefore, I have to tell you to be SURE to ask your doctor permission, first, before doing any icing whatsoever. (even eating cake with icing on it LOL...)