Cyclist, can you help with my question below.

I seem to have injured my LTN in a fall from a bike several years back and have been working on reactivating my right serratus. I can feel a muscle contracting beneath my armpit even if i move my right arm up. Does that mean I can rehab the muscle? Any idea of teh time I'd take and the specific exercises and other muscles to focus on along with it?Also what wre your symptoms. Mine are bilateral TOS, right is (i think) due to serratus issue.
The Levator and Rhomboid are overdominant on the right side because of the serratus issue and I have nerve pain and compression in my right arm and hand.

Left is due to injured longus colli which is not stabilizing my cervical spine. I have constant pain in my right shoulder/neck area, I think overstressed levator and upper trap and also a supraspinatus injury probably.

So if the Serratus is contracting each time I raise my hand, is that a good sign (that its weak) and not that the nerve is overfiring (as it doesn't mostly pain/contract otherwise) and I can rehab it? Any idea of exercises and time it'd take?