All major religions talks about heaven. Heaven is defined as a place where everything is just the way you want it to be and you are ultimately happy. Is happiness possible without suffering?
I guess, happiness is relative to suffering. for e.g., If we suffer in sun for some time, then shelter gives us happines otherwise it is merely a shelter. Cold and hot are not two different entities but one (temparature). Removal of cold is hot, removal of hot is cold. If there is no suffering in heaven. How would we feel happy ?
p.s. Nirvana (which is said to give eternal happiness) is a different state, where time and space converges. or it means nothing to you. It is not a domain where you get everything you want as in Heaven, but a state where your likes (wants)/dislikes does not even exist.