Right Lat More Solid Than Left

My right lat is a lot more solid than my left. Could this be due to always using the same grip while deadlifting? Also what could I do to balance this out.

Whatever the reason, you should work both grips equally.

You mean you use a mixed grip? I always swap which hand is pronated and which hand is suplanted every set.

That is just common sense!

And before anyone beats me to it, you might like to switch hands when you have Mrs Palmer and here five daughters over for a visit!

You’re just a natural-born right-winger. Better than being a left-winger, IMO. Sorry, couldn’t resist a bad joke.

Yeah, switch your deadlift grip every set. And try doing some one-arm lat pulldowns - that’ll show if your right lat is actually stronger.

This could be due to several things. Remember, solid is not always a good thing. It could be from tension, knots, scar tissue or this huge abnormal cyst that is going to grow a second head (probally not this one.) We don’t know by what little info you gave us. But don’t be so alarmed.
Like mentioned above, be sure to alternate grips on your DL. Do one armed exercises. Use the same weights and reps for both arms, even if one side can handle more.

Is it in your dominant side? If so there shouldn’t be too much alarm since basically both sides of our bodies aren’t 100% alike.