My boyfriend of 2 years is pretty vague when he tells me about his day at work or what he is doing at home?

My boyfriend of 2 years is pretty vague when he tells me about his day at work or what he is doing at home when i ask him over the phone how his day was, or what he is doing. His responses are usually like, "i'm just organizing some stuff," or, "doing some stuff," "just relaxing," "my day was good," and he doesn't get into details or be a little bit more specific about it. I have to ask to be more specific in order for him to do so. It seems like he is not comfortable going into details. Is this normal? Also, i trust him 100% in terms of faithfulness. It puzzles me because we all want honesty, and is being vague considered honesty? How come some people are not comfortable being specific about what they are doing?