Probably just a virgin muscle, for me Cyp actually hurts more than prop, but that is just me, different for everyone. Either way, it will get better assuming you are sterilizing properly. Might try and inject VERY slowly, without moving the needle(as to avoid scar tissue). I'm assuming you're probably shooting 250mg? so 1ml? If so try and take 30 seconds(might be alittle excessive) to inject, let the oil dissipate, then once its all in, let the needle sit for another 30 seconds and then pull it out. I find that when the PIP is bad that on top of alittle massaging, sitting on a HOT heating pad for 10 mins helps significantly with the pain/irritation.