Whenever fielding outside the 30 yard circle, a fielder have to make harder and faster throws(and every time I end up with a painful shoulder).
How to effectively throw the ball from outfield without shoulder pain/injuries?
This site gives a description of throwing technique for a cricketer:
It describes the side-on technique, where you point with your non-throwing arm towards your target and you then can use your weight to provide impetus to the ball.
For a different, front-on technique, have a look at https://www.youtube.com/watch?v=MCvtnyqG4MM