What Causes Severe Pain In Shoulder, Neck And Back With Numbness In Hands?

Hi, I have a question... I have had horriable shouldet/neck/back pain on my lefy side over a year went to the er a few times and they say nothings ong but now my right side is doin the same thing... And my hands are numb alot of the time and I have troublr functionning my hands occasionally and ocassionaly arms/shoulders get brighy red and feel like there on fire... Do u have any idea on wat could b wrong..