Having worked with veterans, I know firsthand how difficult it is for them to share some of their stories with those who have not experienced combat or life in a combat zone. This is exactly what I thought when King and Reno echange that look---this was a story that they could not share with soemone who had not been there. I see it now working with people affected by cancer---sometime people don't "get it" and it can be more hurtful/stressful to share than to keep it to yourself or share withsome who is lving that life. Do secrets build walls? Yes, without a doubt AND I also agree with kellilee-- there are times when sharing an experience, secret, feeling is not in anyone's best interest.
I think we live in a culture that overshares---social media has made it easy to share instantly and many times without thinking. One consequence seems to have been an expectation that everything has to be shared--that having private feelings, memories, experiences is harmful at worst, not beneficial at best. Becca's attitiude is one I agree with---contrary to cultural expecation, there are stories that are not meant for public consumption. Is her decision to keep her college plans a secret a bad one? In the context of healing her relationship with Ben, perhaps. In the context of wanting to own the feelings of accomplishment and not tie them up with her relationships, no.