I'm a meth addict who shoots up meth. I am now experiancing pain and soreness above the injection site. What is this from?

See below. You possibly have a local infection or local phlebitis, and need to see a doctor asap. At your age, you have a world of possibilities ahead, but you will destroy yourself if you continue meth. You need help now. Get off the crap and change your life. See your doctor today.
Cellulitis. If you have pain fever redness chills risk of cellulitis even can affect your heart see medical doctor.