I am 35 year old, and about an hour ago had a sudden onset pain in the back of my neck on my left side. About 30 minutes later, I attempted to stand up, and my legs are very sore, the muscles are very sore, to the degree that I feel a bit unsteady trying to walk. I also have a rapid heartrate, of about 130 beats per minute, which is a little high even for me. I am a smoker, and had just finished eating lunch.