when I first started playing I was the same way. RC was 'pull' for me. I hit a lot more right down 1st base line than I ever did to the left of 2nd base. I'm a righty btw.
anyway, after a while I decided it wasn't 'right' and I should learn to pull the ball. can't say I did anything special, I just tried to pull the ball in BP, and learned how to do it. problem was I had 'change' my swing to do it, and then hitting oppo became difficult and weak for me. for about a year I had this issue and trust me, not being able to pull the ball is WAY better than not being able to go oppo.
it's like the fielders just assume you can, so you never see the kind of shifts as you do if you pull everything. not to mention that hitting the ball to RF is so much better than hitting to LF.
anyway, my advice would just to work on it a bit in BP, but don't make it your ultimate goal. make sure you don't lose the ability to hit oppo
if you can do it in BP, pay attention to the pitches. I know exactly what type of pitches I don't hit well, and when I'm thrown those in games it stops me from being able to place my shots. in BP I let them go most of the time, but in games they often get called strikes, so I can't let them go all the time. it's good to be a little picky in BP, but it could be that you're actually being TOO picky. it's easy to spray a ball that comes right down the middle. it's a lot harder to that with one that's hitting a corner