It all depends on your faith (meaning what you believe in).
Is it a sin? YES! If your looking for excuses to make you fill better then you will find several.
Is it better then getting a girl pregnant (that your not married too) or catching STD's? OF COURSE!

I know plenty will argue with this but your question is "is it a sin" the answer is simple "YES" the work around and your personal questions (how Lord?)is the hard part! The truth is that God didn't design us to be single (Genesis 2:18 Then the LORD God said, "It is not good for the man to be alone. I will make a helper who is right for him.")
He created man and woman to be together. Were just complexed with all the things going on today, money, lust, trust, bills, school, work, etc... and these things stop us from finding "a helper who is right for us".
It took me 29 years (starting from birth - lol) to find "a helper who is right for me" THANK YOU JESUS !!!! lol
I pray you find what your looking for brother - God bless!