Since no one has answered, I think I would give it a go :P
When there isn't a clear diagnosis, and you've been to physiotherapy, I would think your problems are bought on by your postures.
At your age, your joints are probably starting to get stiffer, and maintaining the absolutely best posture is probably very difficult. I think you are heading the right direction, putting more attention on the posture. However, have you thought about the possibility that you may have done too much?? Of course, its kind of premature of me to suggest this before actually looking at your posture.
From the sound of it, I think you're probably doing too much rather than too little. Just take a minute to think about what you do when you correct your posture. Do u tense up your back muscles to keep your back straight? Have you ever checked that you could be arching your low back too much?? your winging scapular....why is it winging at all......is there a nerve palsy?? probably not.....my guess is that you keep you shoulders forward most of the time, not that you do it intentionally, but rather a result your increased thoracic kyphosis, so causing excessive stretching tension to the serratus anterior. No amount of strengthening would work for your winging, because no matter how strong it is, its endurance always has a limit. What about the head posture, have you read anything about "forward head posture" yet. Head, scapular, upper and lower back are all connected into one functional piece, and you cannot change any one thing alone. you need to consider all of them as a whole, change everything at once. Afterward, you can work on your hip position...but don't worry about that right now.........its getting too complicated at once already.....
Research on "Alexander technique". It is about finding the most efficient way to use your body, i.e. eliminate excessive tension. It has worked wonders for a lot of people, and after what it did for me, I've been recommending it to a lot of people. It is useful in more ways that you can comprehend, but its only good once you truly understand it. I would suggest read some books, watch videos (youtube), and maybe take lessons too, mind you they are expensive!! Its actually a difficult concept to learn initially, but if your are a "Determined Rehabilitator" you should have no problem. It took me ~2 months to start seeing progress....so keep at it.
Good Luck.