is it good for health? do it have any side effects? Like affect height or something
No, it doesn't affect your height.
If you do it a lot obviously it could cause some soreness, but you'd know about that.
how long does the sore pain lasts normally ?
The longer it lasts, the more you have been overdoing it, usually.
If you masturbate so much it makes you sore afterwards, you're probably overdoing it a bit.
It is good for you sex life as long as you do it the right way. If you spend years doing it as fast as you can and not learning to control yourself, then you may end up with premature ejaculation.
But if you use it as a way to learn about your own arousal levels and teach yourself to last longer before coming, then you can end up making yourself a much better lover for your partner.
Just a tip that nobody's mum or dad ever tells them;-)