During his working day?! Yes, you are being unreasonable.
He's not allowed to text while driving and he's working with his hands in a job that needs his full concentration.
Remember the world before mobile phones? When we'd go to school or work and our parents and friends could only communicate with us face to face or at home? It's like that. Why do you need to message and check in with him during the day?
I'm busy when I'm in work. My husband is busy when he's in work. We can chat in the evening. He also works a job where he's handling heavy machinery so I fully understand that we can't be messaging all day. Or I could but I shouldn't and don't expect a reply until he has lunch or is finished.
Why are you phoning him? He doesn't need to be texting you through the day. What are you trying to tell him that he won't find out when he gets home?
I totally get messages like the following, which are normal for my husband and me:
"have you got plans for tea? I can go to Lidl after I drop (child's name) to (child's hobby)"
"if you're going to the gym, do you want to give (child's name) a lift back because he's there already"
"just FYI, that package from (shop) arrived, I've put it in your wardrobe"
I will only phone if there's an emergency like a child who needs picking up from school because they've been sick and I'm in a meeting in another city. Sometimes I'll forward a silly meme or joke or video if I see something that'll make him laugh while I make a cup of tea on a work break. But I don't expect a reply immediately.
Are you lonely? Do you see friends and family during the day? Do you work?