I feel like my left mastoid bone is slightly larger than the right. im a little bit worried it might be a middle ear infection however i feel no pain at all just a little weird if someone can help me figure out what this is or if its normal to have?

The mastoid bone is in back of but does not participate in a ransom middle ear infection. An untreated infection or series of infections over weeks and months might involve some of the mastoid air cells. People are not identically formed on both sides and any perceived difference may just be from natural difference in the sides. An ENT could sort this out if needed.

A slight asymmetry in paired organs is normal. Left breast usually hangs lower. You may watch and wait, if the size is stable, you may ignore it. If it gets larger or you have other symptoms about your ear, see and ENT doctor. Wish you good health!