My Contraceptive Implant Is Itching Really Badly I Ve Had

My contraceptive implant is itching really badly i ve had it Since december 2015 and every now and then it will feel uncomfortable weird pain for a couple of minutes but at right now my upper arm is becoming very warm and i feel as if. Its kind of a burning sensation on my implant, its not sore its unconfortable, could you tell me why this is happening ?