I never studied openings so decided to try it.My plan is to play e4 openings and Caro-kann for black. Now to learn the Caro-kann,I have to look at the Advance,exchange and Nc3/Nf6 stuff variations. After e4,if e5 I will play ruy lopez which also have variations like chigorin,breyer,exchange,etc. For french defense I would've to look at exchange,advance stuffs. This all seems like a hastle.I thought chess was a intuitive game,how can I memorise all these?,Any tips?
The answer depends on your strength. Unless you're a master, the answer is "no". Note that memorization of opening theory is easier the stronger of a player you are (as most moves will become "obvious", so you won't need to commit them to memory).
At this stage in your development as a chess player, the best thing you can probably do to help the study of openings is improving your chess skills (tactics and strategy).
But you can make the test yourself. Take a sample of your last few games and check how many of them would have had a different result if you knew by heart the lines you're about to study. The answer is probably "not many of them".
Ultimately it depends on what you want to achieve. If you want to master openings for the sake of mastering openings, then yes, you should memorize all of that. But odds are that what you're actually trying to improve is your overall chess strength, and there are definitely more effective ways to achieve that than rote memorization.