Suggest Treatment For Stiffness In The Neck

hi Dr,

about a week ago i started with a stiff neck that has developed into relentless pain both in my neck (slightly on the left side) and down my left shoulder, i'm taking paracetamol/codeine 1000/60mg to no affect, today i went to my doctors and he said i may of sprained my neck muscles and that could be affecting some nerves he gave me a perscription for diclofenac sodium 50mg (taken 3hrs ago, not worked)

after leaving the doctors and because of the question he asked it got me thinking and i remembered banging my head at work, i was stepping upwards into a machine and banged my head on a pipe but i wear a bump cap so it did not hurt and caused no damage to my head, it just jarred my neck as the blow was quite hard, i just carried on as i was in no pain, i woke the next day with a stiff neck, the pain is worse when i lay down and getting up is scary i'm in least pain when i'm sat up and deadly still any movement increases the pain, the thought of going to bed tonight just made me cry, i'm in agony, should i go to A+E