"Been" and "So" have many meanings depending on how they are used in a sentence, as is the case with many words. "Been" is the past participle of be. Example: I have been in this line for about an hour now" -OR- "I have been trying to understand this for an hour". "So" usually, in my experience, falls under definition four and five on dictionary.com: 4. to the extent or degree indicated or suggested. 5. Informal. very or extremely. Example: "I have been so tired lately." -OR- "I was so upset that I started crying".