Okay, this is going to seem like a mouthfull, so I’m going to bullet-point it for ease of typing and interpretation…
-Pain along the medial border of the scapula is VERY common.
-The location of the pain is rarely the origin of the pain. Usually, it’s referred from another area.
-The most common “other area” is the cervical spine (more on this below). It may also be related to inflammation/injury in the shoulder (probably the case here - examples include rotator cuff strains, tears, tendonosis, or even transverse humeral ligament rupture), and even gallstones.
-There’s no obvious anatomical link between the cervical spine and the location of the pain along the scapula, as odd as it may seem. Nonethless, clinical observations have allowed practitioners to theorize about the possibility of two syndromes: Splenius Cervicis Syndrome (medial scapular border pain) and Levator Scapulae Syndrome (superior border, a bit more laterally).
-These terms were coined because of apparent neural distribution patterns and the fact that these two muscles seem to “send” pain to their inferior attachment points.
-Had to research this one…it was Cloward in 1960 who verified that stimulation of different parts of the disc led to different referral patterns. Contrast injections to the posterior aspect of the annulus led to referral to LSS, while anterior injections caused SCS (medial border pain).
-On a related note, this is one reason why periscapular pain is a common consequence of inproper cervical adjustments by a chiro.
-Anyway, specific to your client, the pain is likely located at the T4-T5 junction, and it likely kicks in when she’s been sitting for a prolonger period of time or exercising with poor posture. Cervical rotation or lateral flexion to the same side as the problem may be painful.
-My recommendation is to make sure that she’s super-aware of her posture from now on. Encourage her to move around often; the best posture is one that is constantly changing.
-Have her get to a chiro to check for cervical subluxation just as a precaution.
-Continue to address the obvious issues that she has with shoulder imbalances and scapular dyskinesis.