Pain in the deltoid area?

Injuries
#1

I’ve been having arm pain in what seems to be the deltoid muscle. What can possibly cause this?

Deltoideus.png510×502

My pain is not above the shoulder though (but still where the highlighted area is), its more on the side of my arm, I guess between the biceps and triceps.

#2

Also, I should probably note that while I’ve iced and rested the arm, I still have pain about 2 weeks since I first noticed it.