The Buddha taught that suffering is the extra pain in the mind that happens when we feel an anguished imperative to have things be different from how they are. We see it most clearly when our personal situation is painful and we want very much for it to change. It's the wanting very much that hurts so badly, the feeling of "I need this desperately," that paralyzes the mind. The "I" who wants so much feels isolated. Alone.
Pay Attention, for Goodness' Sake (ed. Ballantine Books, 2007) - ISBN: 9780307416353