So far I have shot one CC of test E 250. I planned on shooting twice a week 1 CC at a time. The past two times I worked out I experienced a pain at the back of my upper neck toward the bottom of the back of my head. Basically an intense headache. But it only occurs when I'm towards my last reps or when the work out is very intense. But it hurts enough that I have to stop working out. It seems to happen more when I first start working out and then once I'm warmed up and a couple of exercises deep, the pain then becomes tolerable and starts to fade away. Has anyone experienced anything like this? Can it be that my body is getting used to the test? Any insight will be much appreciated.