What Causes Constant Painful Muscle Spasms?

Hello, my left forarm's pulse is going crazy. It never did anything for a long period of time like it is now. Every few seconds it feels like my pulse is going to pop out of my arm. I can also feel my left leg doing it too. I hurt my neck along time ago, but I went to the chiropractor two months ago and he put my neck back into place. Currently my neck isn't hurting, so I don't understand why I'm having constant painful muscle spasms. If someone could help that would be great :)!