So your computer said "sitting too long in a chair with your father"? lol, we may need to pray for your computer. ;)
I don't think I can imagine lounging with a laptop...but the tub thing sounds good. However, the last time I was in the tub taking a strong therapy soak, I reached for my smartphone and the screen went nuts. I had dried my hands before I touched it, but the energy of the soak I think made all sorts of windows open up on the phone and buttons were being pressed. It was like it had a mind of it's own. So I haven't tried that again.
I have not had problems with my back or hips in the past while using the computer. It was just went I started using the smaller computer and/or tablet and I started leaning too much forward. I think I do better in an upright position with my shoulders back and my head straight across looking at the screen. Old school position...where the teachers with the wooden rulers use to pop you if you didn't sit up straight. lol
But you are right. Standing up often and getting circulation moving is probably a good thing too.