I had nothing initially, only a slight tingly sensation, but no real growth (the tissue became a bit firmer, but that's about it). After 6 weeks we took another blood sample, and then added a low dose anti-androgen, as my T levels were still in the normal male range (I started high, but my E was fine). Only after a few weeks of anti-androgens did I start getting the classic chest pain. Again no great growth after 3 months, but I definitely feel that something is happening (also been on finasteride for a year now, due to male pattern baldness).
Genetics of course play the main role, but similarly to what the others said, I would go see your endo and maybe get the T level checked. If it's too high, that may be enough to counteract the workings of E in the chest area.