There are non-stop flights from Mexico City to Havana, as well as flights with connections in cities such as Cancun and Cozumel. Your flight may take from 2 and a half hours (Mexico City - Havana) up to 4 hours or more (Mexico City - Cancun - Havana).
Matamoros is on the Mexican side of the border with Brownsville, Texas. Cancun is 1,207 kilometers (751 miles) southwest of Matamoros. You could drive along the "carretera costera" along the Gulf of Mexico, but it is much safer to just take a flight to Cancun.