Have I done nerve damage in my neck?

Around 6 weeks ago I was doing some seated rows in the gym and I injured my upper back. At first it felt like I had pulled the left Trapezius.

For 2 weeks after that, I really struggled to sleep as the pain in my left shoulder was horrendous. I had pain which radiated down my left arm, felt like my bicep was contracting (when it wasn't) and I developed pins & needles in my arm and hand (which has continued up to the present day).

As I actually thought this was a shoulder injury (as that is where the pain was), I was referred for ultra sounds and x-rays which both came back normal.

I am really in to the gym and I went back to train and I have lost a lot of strength in my left side mainly in the shoulder and bicep, but not on the right hand side. I also notice when I stand in the anatomical position, the left shoulder looks a lot more square than my right hand side and the lateral deltoid doesn't look any where near as full. I have included a photo with this post to demonstrate.

Attachment 1441

I do have a pain in my neck area to the left of my spine, and when I depress my chin to my upper chest, I get a shooting pain which radiates through my anterior deltoid and down to my left bicep. I also get the same pain if I turn my head to the right hand side.

Does this sound like nerve damage? Would nerve damage or impingement cause such a sudden and significant reduction in strength in one side?

I had an MRI today but I won't get the results until the 29th.

Thanks for your help.