Mintoo Mand: Said P B Shelley:"We look before and after /And pine for what is not?Our sincerest laughter/...With some pain is fraught.Our sweetest songs are thsoe/Tthat tell us of our saddest thought."There is also a song from an old Hindi movie rendered soulfully by the incomparable Ghazal singer, Talat Mehmood:"Hai sabh se madhur sangeet jisse/Hum dard ke svar main gaate hain."About your question on why love has to be so painful, I think Minto ji, this a a very profound question and not all the books in the world put together can answer this. But I think that it got to do something with the fact that love involves our whole being like nothing else does -- except pain. I might attempt an answer some other time, but thanks for posing the question. The key to understanding life really lies in asking the right questions -- and asking them with sincerity as you have done.