How are memories painful yet necessary? Discuss this in relation to Jonas’s community.

In chapter 8 of The Giver, Jonas is selected to become the Receiver of Memory. The Chief Elder cautions Jonas and the community members that the training will involve physical pain. She says Jonas will experience pain "with a magnitude that none of us here can comprehend because it is beyond our experience." At their first meeting, The Giver explains to Jonas that the two of them will have "hard and painful work to do."
According to The Giver, Jonas must receive the memories because "It is how wisdom comes." While some of the memories are happy or pleasant, many are physically and emotionally painful. The memories are necessary because with the knowledge gained through receiving them, community members can be protected from mistakes made in the past. For example, the first memory Jonas experiences involves snow. The community now has the power of Climate Control. With that power, the community ensures protection of agriculture, but the people are denied the experience of snow. Jonas experiences the pain and discomfort of some memories so that his community members may be protected from that discomfort. However, he also experiences the joy and emotions that the community has lost through their quest for Sameness.