why is my cake uneven on the sides
Some cake pans do not have straight sides. Some of them have angled sides; they sort of flare out. That's the only reason I think the sides of your cake are uneven. Or am I reading your question wrong? Need more info on your cake issue, i.e. what exactly do you mean by uneven on the sides?
This can often be from an oven that heats unevenly, an oven that heats too high, or even not staggering your cake pans in the oven if you are baking two layers at a time. If the cake is tilted, it could be that your entire stove is off-balance. If the cake is domed in the middle, the sides of the cake have set before the middle has had time to fully rise.
Make sure you have completely mixed your cake batter and spread it in the pan evenly. Another tip is to "drop" the pan, or tap it flat upon the work surface to ensure that air bubbles are released between the batter and the contours of the pan. It won't take the volume out of your whole cake. If all these things are checking out okay, then you can "wet-wrap" your cake pan's sides to help them rise more slowly. These heat-safe strips can be found at baking supply shops. Some people wet dishtowels/tea towels, but I am leery of that. Hope this helps!