Absolutely not, but it is not healthy either
So, here comes a mom lecture. I do think sitting behind a computer all day is not good for anyone. You need to be up and active. Take breaks and stand up, stretch, get outside, do some sports/exercise, etc. A good exercise is to hold a towel behind you and pull out with your arms--- stretches out your back. Do you lose height because of sitting behind a computer? No. But you can get hunched over and posture problems if you don't watch yourself. And if your hunched over with bad posture, you don't appear as tall. :) I have a son who is cerebral and works hard on his homework and such so spends a lot of time over a computer. I make him stand, stretch, put his shoulders back, support his lower back, etc. So, keep that stuff in mind. But you won't be shorter because of this in terms of how much you grow. When did you go through puberty? That is a bigger determinant of how tall you will be--- that and the height of both of your parents. good luck
No. You will grow to whatever height your genes have programmed for you absent some severe malnutrition episode which occurred in childhood, such as happens in war torn nations or nations with an economy that has completely fallen apart making adequate nutrients impossible to obtain. This isn't you. It might, however, lead to problems with your spine later in life, such as neck pain and shoulder pain, so make sure your posture is good and you don't spend all of your time doing that. You gotta get out and move, you're an animal, you're built for movement, not sitting around. Bending your neck down greatly increases the weight it puts on the the vertebrae that support it. It's even worse if you spend a lot of time looking down at a cell phone, so try to keep it a eye level when you look at it. This also has nothing to do with height, but if want muscle development, again, you gotta get out and exert yourself. Now, if you're busy writing great music or writing great literature or making great music, it might be worth it. If you're just surfing the web, playing video games, or hanging out on social media, go gain there at all. Moderation. Peace.