is it possible for there to be a purpose for suffering? yes. it can help us make progress to end suffering. we are co creators in that sense. it can give people the perspective to appreciate no suffering. as jesus said, the man wasn't born with health problems because of something him or his parents did, but to give glory to God when he's one day disease free.
also, asking why we still have suffering is like asking why darkness exists. that's just the way it is. can we have just light? i dont think that is possible in our reality. same way, suffering may need to exist in this reality too.
of course, a person can just insist that if it's possible for suffering not to exist but does, then it isn't necessary. a person could rationally cling to that principle, but they have to admit that they might be wrong if everything i say is true, and they need to admit that the alternative view that i present is completely realistic. What if God and heaven exist, and the reality is how i present it? then the skeptic is just clinging to philosophy that has no basis in reality. the words and thoughts, the pointless ramblings, of mere men.