I thought I'd throw my story into the thread since it's so similar to those who posted before me. I can only offer prognosis data, as I can't afford medical care. I'm not looking for diagnosis, just to offer my story which can hopefully help pros or others.

Origin of injury: No flu shots. No significant medical issues or history. 35 yrs old, resistance training average 4 times a week since age 14. Early January, 2019. I slept on the couch, which I rarely do, and woke the next morning with severe pain and stiffness in my left shoulder blade/left rhombic area and left side of neck. My wife was scheduled to be inducted for the birth of our child, so we headed to the hospital that night. During a two night hospital stay, due to complications during delivery, my condition worsened to the point of having to hold my head tilted to the left. I normally refuse to take medication, but caved and took some Ibuprofen, but it didn't help at all.

When we got back home, brand new baby in tow, I went to do my first workout since the "stiff neck incident". I normally start with pushups. That's when I got depressed, as I went to lower myself to the floor, my left side gave out and I collapsed flat on my belly. I noted that my left pec and left tricep were essentially powerless and wouldn't flex normally, only slightly. I panicked and began trying tricep pulldowns, my right arm was completely normal strength and flex. My left arm couldn't even move the cable. On the bench, I tried barbell presses, but my normal weight was impossible on the left side, right side was normal.

Over the next few weeks, I did chin tucks, which felt tight in the left rhombic region. I did weighted neck traction with an over-the-door-device. I started sleeping on a memory foam mat on the floor and bought a neck chiro-pillow to sleep with. None of these things provided relief.

0-3 months after the incident: I stopped working out. My triceps would twitch randomly. The pain and stiffness in the left rhombic/neck areas faded very slowly, took about 2 months. I began losing touch sensation in my left pointer and left thumb, could feel pressure sensations though. If I leaned my head back, in a looking at the sky position, after about 10-15 seconds a pins and needles sensation would begin flowing from my left shoulder/upper bicep to my left hand. The longer I held my head in that position, the more intense the pins and needles would get. When I aimed my head back down to a level sight position, the tingling would begin subsiding instantly and vanish completely within a few seconds.

4-6 months after the incident: Still have low activation in left pec and left tricep, and those muscles are still soft. All pain/stiffness is basically gone. Touch sensation returned, maybe SLIGHTLY muted. The "looking at the sky" tingling does not happen anymore. I began a modified resistance training regimen using low weight dumbbells, so I could isolate right and left side strength. I only do on the right side what I can do on the left side, to hopefully maintain body symmetry. The left side fatigues faster than the right side during workouts. My left side makes very slow gains, I had to buy fractional olympic weights so I could attempt to make strength progress.

Today (7+ months): Still no improvement to strength or muscle hardness in left pec or tricep. No pain, tingling, stiffness. The only notable anomaly that remains is after my cable back workout, if i try to touch my shoulder blades together, it feels like a balled muscle in my left rhombic area. This dissipates by the next day.