Is there a site I can go to or a software which I can use which will help me to analyse a chess position?
That depends on what you mean by 'analyse'. Any chess engine with a GUI will allow you to input a position and get sample lines from the engine, while letting you try out variations. Online services that allow this include http://lichess.org (you'd have to upload a game's PGN there first) or http://analysis.cpuchess.com/.
If by 'analyse' you mean study and learn from the nuances of a position, then the short answer is no - while a GUI might provide a way of easily resetting the board to certain states, it can't do the hard work for you.
I would recommend a few analysis tools. See which works best for you: