From the last few months, i feel electrical current shock in the right upper half of my body sometimes. It happens suddenly. Like when I am walking or sitting or doing something, that current suddenly comes and goes in 3-4 seconds or sometimes in a bit longer. I feel that electrical current from my right underarm to right breast. The position of this current is fixed. I've felt this for around 14-15 times in last few months and always on this same right underarm to breast part. Its not painful. I only feel like a sudden hard electrical shock for some seconds. It was regular for around a week in starting but then it started happening sometimes only. What could it be and what should I do?