stocks are like the class 10th bunch. all are together during 10th/matriculation (index). but over time, they all go their way, different from each other and that of the class/index.
so no need to worry about stock price movement wrt the index if the stock selection is right. fluctuations in good stocks on the way up is just a mark of respect to the hiccups of their alma mater.
a portfolio gets torn apart and scattered in different directions like the coagulation of colloidal solutions like milk and blood. that's the formation process of cheese in investing. a balanced portfolio takes care of any churning.
