What MS course should I do after completion of mechanical engineering? ?

Do MS rather than MBA. You cannot effectively manage engineers or business unless you also have the experience of the work that other engineers do. I you are not passionate about what you do, you will have trouble keeping your job, because those who are passionate will produce more and will replace your position. If you just want to earn a lot of money, go into sales. Be the best sales person for the latest heavy industries equipment. Follow the link to know more about ms courses after mechanical engineering