Some post injection pain is completely normal for your first injection. You were probably a little nervous and wiggled the needle during the injection. You made a small bruise in the muscle. It's nothing to worry about at all.
Here are some tips for reducing PIP:
1. Heat up the oil prior to injecting. Run the vial under hot water for 1-2 minutes. Heating up the oil will bring it closer to body temperature and make the oil disperse from the muscle into the blood stream much easier.
2. Gently massage the injection site for 1-2 minutes after the injection. It'll help disperse the oil into the blood stream.
3. I am a big advocate of training the muscle you injected into that day. It'll help disperse the oil from the muscle into the blood stream. In other words, try to time your glute injection on the day you train legs/glutes.
Testosterone enanthate has a half life of 10.5 days. As a general rule, it takes 4 x the drugs half life to reach peak blood hormone levels. 42 days after you start your cycle is when you will notice the full effects of your cycle.
Are you using an AI with your cycle? An AI (aromatize inhibitor) is very important to prevent against estrogen related side effects like gyno and water retention. If you arent using an AI with your cycle, get aromasin and start dosing it at 10mg every other day. You can order it from ag-guys.com if you need a source