Hey [boss].
We need to talk. I was having lunch with [coworker], and he asked me how the tension situation between us was. My first reaction was to tell him everything was fine, but in fact, it's not. This is a new and unwelcome turn of events. This wasn't the case up until a few weeks ago, and I don't know how things went from hunky-dory to their present state. It seems that all our conversations are terse and tense. I have no idea what's going on, which is actually part of the problem. I get very little feedback from you about my work, about the state of the company, clients, prospects, anything. This makes me feel like my input is not important. You probably have issues with me, I know I have some with you. I'd like for us to put them on the table. Are you free for lunch tomorrow or Friday?
A+,
[me]
I don't know what this is going to do. Hopefully, things get better. At worse, well, I'm already looking for a new job right now anyway.