Hi Lucia,
I understand that the new brain theme of not trusting yourself enough holds you in a habitual dorsal-vagus restriction. You don't feel safe and motivated to exercise, unless you activate the sympathetic mode to try and support yourself. But because the structure and muscles have become weaker, they then feel overused and painful. 
A lack of appreciation and connection can be an "old brain" conflict that lies at the base of your self-devaluation. Or which one has been with you longer?