From time to time I will come across an article that says these verses are not talking about salvation/eternal life, but only about Christian living, in other words; exhorting Christians to walk the narrow "proverbs path of life".
And that God would NOT create "most of his creation" knowing that most of them would choose hell rather than be with Him.
They will say that "most people will eventually get saved" and so these verses can't be referring to that.
But how does that fit with the context?
To me it has always sounded like the narrow gate is believing on Jesus alone for salvation, and the wide/broad gate is choosing 'Jesus-plus' or any other works based way.
Here is my two cents... 
Yes, I believe that these verses are speaking of Heaven and Hell.
But let me explain what Jesus is saying though.
Matthew 7:14 Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it.
What is the strait Gate and narrow way?
That is simple as the Bible mentions
the only way to get to Heaven is belief in and acceptance of Jesus as per the verses below.
Romans 10:13 For whosoever shall call upon the name of the Lord shall be saved.
Acts 4:12 Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved.
John 14:6 Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me.
Now comes the tricky part that most don't understand. When Jesus says
there are few that find it, that would seem that few would go to Heaven,
but it that the case? Revelation 7:9 below would seem to say that a lot more than a few will go to Heaven.
Revelation 7:9 After this I beheld, and, lo, a great multitude, which no man could number, of all nations, and kindreds, and people, and tongues, stood before the throne, and before the Lamb, clothed with white robes, and palms in their hands;
What does Jesus mean when he says there are few that find it?
The key to understanding how there can be both a great multitude in Heaven but only few that find it is the word
find. Jesus did not say few that choose it or few that enter it, he said few that
find it.
Here is the thing. There are very, very few that find Jesus on their own. By far most people are told about Jesus by someone which could even be God himself. Paul in the Bible is an example of this. God came directly to him. I myself did not go looking for Jesus, someone shared Jesus with me. As and example of my point. If you were walking down the road and found a watch, you found it correct? However if I gave you a watch, you would not say you found it would you? So Jesus is just saying most do not find him or even look for him. This is why sharing the Gospel is so important.
I hope that makes sense.
While you did not ask me, I will say I believe more people will be saved than won't. Jesus (who is the light) says that only evil people won't be saved in the passages
in bold below.
John 3:16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
John 3:17 For God sent not his Son into the world to condemn the world; but that the world through him might be saved.
John 3:18 He that believeth on him is not condemned: but he that believeth not is condemned already, because he hath not believed in the name of the only begotten Son of God.
John 3:19 And this is the condemnation, that light is come into the world, and men loved darkness rather than light, because their deeds were evil.
John 3:20 For every one that doeth evil hateth the light, neither cometh to the light, lest his deeds should be reproved.
John 3:21 But he that doeth truth cometh to the light, that his deeds may be made manifest, that they are wrought in God. 
