Is it possible to not be able to grow muscle in a certain part of your body?

I've been working out my chest for 2 months now and I've seen good gains. My left pec is perfectly developed. But only the outer edge of my right pec is well developed while the inside is flat. The inside of my right pec is as flat as it was when I first started working out. I have been doing flies and hitting the inside of my chest during workouts. Is it possible there's no muscle tissue in that area of my chest therefore it's impossible for me to grow muscle there? This sucks. Help me out please.