Why are my jaw and chin so slanted? (Photo)

Hello dear
Thanks for the question and provided information as well. 
My recommendation for you is a personal consultation with a certified plastic surgeon to be able to make a complete evaluation and suggest the procedures that can fulfill your expectations and provide you with the best results.
Good luck :)

You have bony asymmetry of the lower jaw which is most manifest in the chin area. There is likely some asymmetry due to overgrowth further back along the jawline on that sides well. This could be improved by a chin reshaping procedure, removing the excess bone on the one side.