How tough is it to be a physicist?

I'm considering it as a career, but I don't know how intelligent you have to be to write papers on a consistent basis and be a decent physicist.
In all my math/science courses I'm getting mid-high 90's without trying, but is this enough?

It was Thomas Edison, who said that genius is "1% inspiration and 99% persperation". But I disagree. Evetnually more or less everyone is going to have to put in some work, but if you don't have an innate ability, then maybe consider something else because work can get you only so far. Especially when it comes to making big discoveries.