The Diccionario de americanismos is a great tool for these kind of questions.
There you can for example see:
patrón, -na
I. 1. m. y f. Ec. Señor, amo.
II. 1. adj. Ni. Referido a persona, de pies grandes.
●
a. ǁ ~. fórm. Mx, Ho, CR, Ve, Ch, Py; Ur, obsol. Se usa como tratamiento de respeto a alguien.
□
a. ǁ ~ de fundo. loc. sust. Ch. Persona que ejerce un poder despótico y arbitrario. pop + cult → espon.
b. ǁ ~ de prueba. loc. sust. Cu. Gráfico fijo con líneas y colores que permiten ajustar la imagen de un televisor.
c. ǁ ~ grande. loc. sust. Ec. Latifundista o hacendado. rur.
That is, a great set of meanings for patrón depending on the country. Basically (I don't know if you understand Spanish) meaning boss, but also other things.
From what I see in the definition, patrón does not have any special meaning in Colombia, so you can go directly to the Dictionary of the RAE and check the word:
patrón, na
Del lat. patrōnus; la forma f., del lat. patrōna.
1. m. y f. Defensor, protector.
2. m. y f. Santo titular de una iglesia.
3. m. y f. Santo elegido como protector de un pueblo o congregación religiosa, profesional o civil.
4. m. y f. Dueño de la casa donde alguien se aloja u hospeda.
5. m. y f. señor (‖ persona a la que sirve un criado).
6. m. y f. patrono (‖ persona que emplea trabajadores).
All of them can apply here, since Pablo Escobar was seen as something in between a boss, a saint and a protector among his workers.
This being said,
- jefe: this is, to me, the most straight-forward way to translate boss. In Spain is the one we use all the time.
- patrón: as indicated above, this word refers to a boss in a work place. In Spain, I hardly ever hear it in colloquial conversations, but (as noted by Nox in comments) it is used to mention the captain of a ship.
- capo: is normally used to refer to mafia bosses and it comes directly from the Italian (capo means head in Italian, and in Romanic languages head also means leader).
So if you want to jokingly call Boss to your girlfriend, I would go for Jefa. Unless you are in some smelly business together and you want to call her capo :)
Bear in mind, though, what DGaleano comments below:
I understand that Mexicans call their mother "la jefa" or "la jefecita"... so please check this out before you get into trouble with your girlfriend. Here a link for that http://www.tubabel.com/definicion/1106 "La patrona" could work better for Mexico