Inject every 3 days, rotate spots.
I like lats, delts, glutes. that 6 sites right there.
if it really hurts put the vial in a pan with some water. heat up the water so the oil gets thinner so it doesn't crystalize inside you. that's where the pain comes from.
if it still hurts after, get an electric blanket/ heating pad and hangout with it on your shoulder.
swtich from icy hot to the pad.
if you're still in pain after that go see a massage therapist and get a deep tissue, esp if you inject legs and accidentally hit something. that's why i don't do legs anymore.
IF THAT DOESN'T WORK go to a sports medicine doctor and get a help with their therapeutic toys.