I (M13) have been going to the gym for some time and have gained muscle particularly in the upper back. However my ribcage is visble and I can't quite get that V-taper because of how it sticks out. If it helps I'm 5'9, 58.1kg/128lbs, and have a bodyfat% of 10.3% according to a beaten up scale that is older than I am. Do I need to put more of an emphasis on my lower back or is it another muscle that needs help?