What Causes Terrible Back Pain And Neck Stiffness?

I am running 2 or 3 times per week and on Saturday I run but I did not feel very well and I stopped. Next day I got a terrible pain in my back, left side, my neck is very stiff and I cannot look down and my left arm. I ve also got pain in the back of my eyes. I bought a cream called Voltarol but I am not sure if this is teh right treatment, Shall I be worried? Can it be my heart? I am 34 years old, size 6 and I am running since December.