Pain in Neck

I developed pain in my neck, shoulder and arm.  I woke up one day with a stiff neck on my left side.  I tried to treat it using heat and ice packs and ibuprofen.  A couple of days later I went to the ER where they told me it was a pinched nerve in my neck. I had been doing alot of repetitive work and believed the pain was from my job so I turned it into Workman's comp.  The company doctor I saw said I had a sprained shoulder and arm prescribed meds and sent me home.  A couple of weeks later with no improvement, I was taken off work, they then said I had a sprained neck, thoracic, shoulder and upper arm.  I started physical therapy.  I have pain in my neck and down my arm. My thumb, forefinger, and middle finger on the affected side are pain and numb at the same time. I have to sleep sitting up.  If I turn my neck a certain way pain shoots down my arm.  They recently took xrays that show compression in the disks in my neck.  The physical therapist is mericiless.  He keeps trying to lift my neck, he pushes and pulls which causes spasms to go down my arm as well as pain and numbness.  He says my problem is caused by my posture not by the work I did.  
My question.  If I indeed have a pinched nerve with beginning stages of arthritis as the ER doctor stated, can the Physical Therapy cause more harm by pulling on my neck and treating it as a sprain. Also, why would you squeeze hard on someones neck, shoulders, etc if they did have a sprain. Shouldn't it be gently massaged?
Thank you