I had a similar experience with the pain and weakness, but my injury was obvious.
I was playing flag football on astroturf and got knocked down hard. I landed square on my ass and jolted the hell out of my whole spine.
I had the "hit by a hammer" feeling right between my traps. Then significant weakess started setting in on the right arm. the front half of the tricep horseshoe became almost non-existent.
This happened in California in Oct. The docs put me on traction, massage and PT etc because the MRI was inconclusive. The PTs kept telling me that the arm had atrophied. I knew that wasn't right.
I moved to OK in Mar and sought a second opinion. New MRI showed some disk damage and stenosis.
Surgery in Jun. C5-7 disks removed and replaced with cadaver bone. Then the vertebrae were fused with a titanium plate and 6 screws. Wait 4 months, then rehab.
After the surgery, the doc told me there was a lot more damage, scarring and bone spurs than they had anticipated.
Basically, the bulging disks were cutting off the electricity to my right tricep. It's still shaped a little funny and a bit smaller than the left...