Missing Brachioradialis Muscle

I sustained a series of injuries to the left side of my body. It’s hard for me to pin-point exactly what caused this cascade-effect that occured, because it didn’t occur as a result of a traumatic injury.

First of all, I partially tore the bottom part of my left bicep about 6 years ago. The injury healed and I regained a lot of the strength in that arm. 2 months ago I suddenly had severe pain in my rear deltoid that started as a pain in my trapezius/subscapular region. That pain travelled to my rear deltoid and eventually caused severe pain to the point where I couldnt sleep unless I sedated myself. My left arm became very weak, and a noticed that if I make a motion as if to do a hammer curl, there’s literally no brachioradialis muscle popping up on my left forearm like there is on my right.

Just like my rear deltoid, if I push into that area hard with my fingers, severe pain results. I was also having burining sensations in my wrist as well. my physical therapist notified me that I have large, swollen trigger points all over my back, that are probably a result of years of overtraining.
Anyone else experience anything like this?