1)
What does the Pasuk mean when it says that the angel "found" Hagar by the well? What was she doing there?
1.
Seforno: It means that the angel found her ready to experience a Divine revelation. In fact, she was Davening to HaSh-m. 1
1
As is evident from 16:11.
2)
Where was "Shur"?
1.
Seforno: Shur is also known as Chagar, 1 a town on the border between Eretz Yisrael and Chutz la'Aretz.
1
As Onkelus translates it here, and in many other places (see for example, Bereishis 20:1).