I think it's absolutely fine, it's just how online communication has evolved now. These days, for many people, particularly younger people and heavy internet/chat users (myself included), instant messages on WhatsApp, Messenger etc are not like emails that you "compose" as a fully-formed message with a beginning, middle and end, and then send. Some people are the opposite of this and treat messages like emails or letters, e.g. some family members of mine will write messages like this:
Hi Emma. Thanks for the lovely pictures. I hope you've had a great time. We are on our way to visit gran now. Love from Jackie and Mark.
To me this is more like an email or a message from someone you hardly ever speak to and I find it stifled and unnatural in an instant message with a close family member who you send messages to regularly.
Another thing to remember is that we used to have to log in to computers in order to send instant messages, and then sign off when we are done. You'd have acronyms like BRB or TTYL because when you stepped away from your keyboard or logged off, you were away and unreachable. Nowadays with smartphones, we are never away, we are never unreachable, and we are never logged off, we are always online, logged in, and potentially ready to chat. The conversation is always ongoing so there is often no need to say hi or bye, it's just always open and always there.
As a result it's more like a real life conversation with someone you are in the same physical space with, it's fluid and more like real life speech. If you were chatting with your partner in real life or on a telephone call, you wouldn't speak in a long paragraphs and wait for them to reply. You speak in short snippets with pauses between, so more like the example you gave about the ears being checked at the GP!
However I do think that while this makes sense when you're speaking on the fly, e.g. you're out and sending updates and questions about what you're getting from the shop etc, it can be annoying when people type this way when it's a really long story that they're telling you. Sometimes when you have a lot to say it does make more sense to go back to the old full paragraph approach!