I'm having problems with my left arm it goes numb and pain in my head goes down my left and i always have a headache?

Many possibilities: That can be a nerve problem, stress or anxiety related, migraine or related headache, and rarely cardiac, especially at your age if you have no cardiac history. It may also be related to a past injury, for example if you are or were an athlete, from inflammation or a disc problem. You really have to get that checked out by someone who can examine you in person and get a better history.