Left arm sharp pain which changes.

From a month, I've been experiencing this pain in my hands - mostly left hand (although i experienced it with right hand also a few times). The pain started at shoulder level a month back. Now it constantly changes locations on the hand like forehand, inside inner side of bicep, near elbow and recently pinky finger and. Lower part of thumb. Its not constantly there..comes...stays for few hours to a day or two...vanishes for some days and comes again. I can confidently say that I'm not straining my left hand. Pain peaks before sleep and lowers in the morning. Its not too much pain that makes me keep awake at night but definitely large enough to spoil my concentration at work. I do software job and use my right hand for most of work. But dont understand why left hand is paining. Is this something that i need to worry?