Yes, it's normal. Usually the Propionate ester within the Sustanon is the culprit. Pin a little higher and further to your side so you don't get any pain when you sit down. Make sure you rotate injection sites. Just be glad you're not using Testosterone Propionate on its own.
In addition to being jacked, I believe Cub is right on the money. Although I had no soreness the times I have done Sussie, I did have 2-3 days of soreness every time I did prop.
So Cub's suggestion of rotation plus up and over on the glute is good call.
Just a note, if you include a quad injection in your rotation, I personally buck conventional wisdom and instead of poking only the vastus lateralis, I include my rectus femoris as a spot in the rotation. If you try this though, you might want to flex it first so bring out separation, that mark the belly of that quad head, so you don't miss and go between two heads or end up hitting a thinner strip like the sartorius. Hopefully that did not come across as patronizing or condescending, as I am not sure how much exp you have sticking yourself.