How do you solve a problem when you can't put a finger on it?

There is this vague atmosphere in my marriage. We have had quite a few small arguments but we got lost in them and just disagree over I don't even know what.

I don't feel like we can have a healthy conversation anymore and quite frankly I have lost all interest in talking. Am not giving him a cold shoulder but I don't feel like am heard anymore so why say anything. We greet eachother and that is about all the conversation we can have.

Feels like if I mention STH that ain't right, eg, the car won't start, before I know it, he is talking about how the fridge is dead. (Metaphor) I can't even quite follow how one problem leads to another and this just leaves us not tackling the car problem. Am ist tired of it all. Wonder if just keeping quiet and never saying anything that bothers me about our relationship is the way to go.

When I tell him STH about my day, he says nothing to continue the conversation and if I ask him why he ain't engaging, he says there is nothing to say about it. And now, he tells me about his day and I don't feel like engaging him to tell me more either because I feel all he does is talk about himself and not interested in what I have to say. He is interested if I talk about our son.

According to him, we are very fine. I just feel low and I can't even say what exactly is bothering me. I just feel like I can't have a normal relationship with him anymore.

Can someone see the problem in our marriage? How can we beat this?