No, I think he means the classic "don't look at me" or the dude he sits a computer all day posture.
Forward head, shoulders rounded forward, kinda like the Hunch Back look.
OP there are a lot of variables but you need to stretch out the strong muscles and strengthen the weak ones.
Its a synergistic relationship, actually the proper term is length-tension. When one is out of whack the other will compensate.
Now identifying which ones are strong and which ones are weak is probably where you are going to struggle.
Without being able to see you, and if you DO spend a considerable amount of time in front of the computer and in bad posture throughout the day, I can tell you that your lats will be tight, your upper traps will be weak (not tight) as so many PT's always think and your lower traps will be weak as well.
Go on Youtube and look up Wall Lat Stretching. That will help you immensely. 1-2 sets of 15 reps.
Also your Pec Minor will be tight as hell, its the area between the outer part of your upper chest and the bottom part of the shoulder. Look into stretching this as well. 1-2 sets 15 reps
Also look into Face Pulls to strengthen your upper/mid/lower traps to keep those shoulders in place. 2 sets 15 reps
Chin tucks against the wall would also be a great idea to help that forward head. 1 set 20 reps
A lot of people sit with their head in forward posture, which is essentially shortening their neck and weaken the upper traps.
Instead elongate them by tucking your chin towards your adam's apple, that is the proper position for your head and gives humans the best range of vision possible.
Also in your everyday life think about the things you do and what position you sit in, stand in etc. Usually postural dysfunctions come about from the patient having bad habits without realizing it.
If you don't correct the dysfunction in your posture in everyday life, you will not improve even with the rehab exercises. There's 24 hours in a day, sitting/standing in bad posture for the majority of the day will outweigh 1 hour of rehab exercises.
As for shoulder position, keep your shoulders back at all times.
Your shoulders should look like a T when you look in the mirror. But most people have postural issues and weakness in their back so their shoulders look more like a roof top or an upside down V. Very common with weightlifters too because they are imbalanced and focus on lifting chest and biceps so much over their back.
Right now, I bet your probably leaning in towards the computer screen, rather than having your back completely against the chair.....
All very common things....
Hopefully this gives you a start, I would do the stretches and exercises 3x a week with a day of rest in between.
PIMP