Last week monday night i felt a small bump on my arm with a little blue around the next morning up till today it has been blue the bump is stil their feels like a little rock under my skin?

What else?: Did you pull any muscle or tendon from straining your arm excessively (weight lifting?)? Did you get bitten by an insect? My guess is that this is from a hemorrhage which will likely take a couple more weeks to go away often leaving a yellowish tinge on the skin for a little longer. If the lump fails to improve or gets larger, best to consult your doctor.