one night i was cleaning our bath tub and when i stretched my left hand i felt an electric shock on my left elbow, and my forearm was numb for 10-20mins. Ever since that happened, i can feel the numbness of my forearm and my hands goes hot, and sometimes the numbness goes up my upper left arm and the left side of my back from time to time.. can someone give me an advice on what it is and what to do please?