It is difficult to say with certainty but I do feel it could be the needle size as well. I would recommend trying to pin more frequently as well and obviously rotate sites but certain sites, like your quads and delts, may not be the best choices for primo injections. You may want to try...
I see you are covered but I do want to echo that Anadrol is definitely something to wait until you have much more experience to start using. It is not a rush or race so save it for when it is more suitable. There are plenty of other better options as a newer user