Chest is a good spot. There are 3 places on each pec you can use...here is a picture to give you an idea of where to inject.
*The middle spot seems to be the easiest for most people.
*The top of the pec is good for some, but if you're upper chest is lacking a little, you might opt for the middle one only.
*The bottom spot on the outside of the pec...personally, this spot is always a major pain. Seems to hurt pretty bad...at least for me and a few others I've talked to.
Long and short, the pecs are a good spot to inject...easy, convenient, hold a decent amount of oil, and relatively painless if done in the right spot.