This can be caused by referred symptoms from the Serratus Posterior Superior, an accessory respiratory muscle which attaches to the spine and ribs. Practitioners rarely consider the importance of the SPS let alone know how to assess it.
If you are Asthmatic, suffer with stress or anxiety or are an athlete, your primary breathing muscles may not to be functioning as they should, so accessory respiratory muscle have to up-regulate. If your breathing is off, this will cause inter-related global compensation patterns to develop throughout the body, manifesting in various symptoms.
Rather than massaging, stretching or rolling the area between your shoulder blades (which would be the last thing it needs if it’s weak…yup, muscles are often TIGHT & WEAK) It would make more sense to ask WHY it’s complaining and what compensation pattern it’s a part of.
There are always two parts to a pattern (Paired Receptor Theory) both of which need to be correctly addressed for results to last. If you stretch or release a muscle in isolation, or just do corrective exercises in an attempt to strengthen what you think might be a weak muscle (hint, it might not be) you are unlikley to get lasting results as both sides of the equation will not have been addresed in relation to each other.
The Serratus Posterior Superior is often Paired with the Serratus Posterior Inferior lower down, as shown in the pic above.
If you can’t seem to shake off that nagging ache, it might be time to call in a NeuroKinetic Therapy Master to work out exactly what’s going on, you’ll be glad you did :)