Soreness Even Without Weights

Hi guys,

I am working on activation and light strength exercises for my serratus anterior and the progress is kind of bad.

A weird thing that i also get with some other muscles, is where they will get very sore even after light work and the muscle doesnt seem to get a higher tolerance for getting extremely sore.

Even when it seems to adept a little, not doing the exercise for say a week will get it right back to being extremely sore even after little volume low weight activation exercises.

Does this sound familiar to anyone, and or could someone explain maybe what is going on or what i can do? I am just trying to make these muscles like my serratus great again.

Im not sure if it can be caused by a stretch and that the soreness is from overstretching ( during band exercises, i am not stretching anything myself) and maybe totally unrelated to any strength increases or maybe it is a common thing when you cant activate a muscle properly that it will keep getting extremely sore?