Hay Liam,

There are a few reasons why you may be having the ache, and honestly I would probably need to really assess you to give it a good diagnosis. Could be a hypomobile shoulderblade? (hypo = tight). The shoulderblade accounts for a lot of the movement in your arm, especially when raised above your head, and sometimes following a shoulder injury, as you have not regularly been using this range, the body's use it or lose it policy kicks in, and your shoulderblade stiffens up. Doesn't make much sense as should likely be more uncomfortable when you bring your arm above your head, but maybe this is stretching it out and relieving your symptoms??? It does fit into your clinical picture of rest making things worse, as your not ranging your shoulderblade / gh joint. Also tight Scaps can also lead to tight Tx/Cx due to rhomboids, lev scap/few other local muscles dysfunctioning due to altered GH mechanics / activity, this could be referring pain to your shoulder/arm? Do you feel like you have a tight neck/middle back @ all?

Keep on the gym work keeping that shoulder technique, and pec stretches etc, can take > weeks to start to resolve!! Just have to be patient and consistent with those.

You could possibly have some further damage to your shoulder which is the cause of this however. An Wikipedia reference-linkMRI would give you an exact picture of your shoulder, the labrum, local bursae, muscles, ligaments etc. If you got an MRI and posted the findings on here, we could definitely help you more! However I am not going to advise you to spend $300+ on an MRI without assessing you first.

If you have had it for a long time.. could be postural related? could be something to do with the martial arts too? It is murderous for shoulders sometimes

Sorry, would love to assess you to really give you an answer once and for all

Just to clarify, this is not the sharp pain you originally posted about right? That has resolved?