I'm 5'6 and 180lbs should i get medium or large?

A medium would work just fine for your height and weight , but if you prefer a more “baggy “ look then get a large but honestly medium will Work

Tengo 44 centímetros de pecho y 95 centímetros de cintura, cuál necesito?

Creo que la médium te queda bien! Tengo 104 cm de cintura y uso large! Bien sino quieres algo justo y usar ropa debajo, usa large!

Whats the difference between 3Xbig and 4X?

Dear Customer, We would like to inform you that this occurs between two standard sizes. Plus-size clothing is clothing that is made to fit individuals whose sizes are intermediate between two different average sizes. This site is for those who feel that XXL is too tight and 3XL will be too roomy. So they can order this size, as it will be comfortable for them. Marketplace Impact Support