[kashmir]

Get someone who knows such things to look you over - sports or rehab physio for instance.

If you have a friend or someone you can rely on, start by looking at how do your shoulder blades lie on your ribs? If they wing then strengthening the muscles between them will help maintain shoulder position - and effectively improve flexibility. Also look at how they can maintain alignment - on all fours position them correctly then move your weight forward and back ie from |-| to /-/ and \-\ (the- is your back staying parallel to the floor :) )

Also look at your thoracic mobility. Face down on the floor chin on floor, arms outstretched in front of you, thumbs together. How far can you lift your hands off the floor (with a straight line from fingers to arm pit). Should be about to get about 150mm (6"). If it's less look at wedging your thoracic spine ie lying on your back, place something 1"-3" high on either side of your spine (I started with two tennis balls taped together, but now also own the torturer's wedge). Lie on it at each vertebra for a few minutes. To get the most out of it arms at right angles to the elbow then right angles again - like you are surrendering)

There is a similar stretch/strengthening exercise you can do against a wall (hands up and holding the shoulder blades down) for shoulder positioning.

Also, consider massage as a way of lossening up tight muscles (won't work on the thoracic spine)