Why does love hurt?

I am in love with you, but why do I feel sad and lonely?
Why does my heart hurt when I am thinking about you?
Why do I have to miss you?
Why can't you be here with me and hold me in your arms?
Why can't we be together although our hearts crave for each other?
Why do you have to be so far away from me and I have to stay alone?
Why do I cry and shed tears for you whenever I think of you?
Is this love?
If it is, then why does it hurt so much?