I had blood drawn yesterday for a CBC and CMP, something that I get done fairly often, and have gotten a deep pain for the first time. My arm is sore to the touch down the forearm, and when I extend my arm it causes more pain and I can t seem to straighten it all the way. There is no visible bruise, but when I touch my forearm there is a large hard bumpy are that feels like a muscle knot and is about 4 inches long. The pain started almost immediately after the draw, and hasn t subsided at all yet. It has been 19 hours now.