Welcome, great intro post, we don't see that too often these days with such detail. That alone is an indicator you should do well.
In regards to your pro sport that you participate in, do they test athletes for doping?
If so, stick to short esters, and light dose of a few orals as needed.
I'd stay away from all nandrolones (NPP/deca), Equipoise, and injectable winstrol. They can be detected for many months and even over a year in some users. This is assuming you are tested.
I agree with whoever mentioned using a 25G needle, as it will reduce not only pain, but also scar tissue that can accumulate over many years of use. Get familiar with how to inject into the quads and also hip shots....they are easier to reach if you are doing your own injects, especially if you have a shaky hand when doing shoulders. Glutes are also another good place to inject, but you probably know this already.
Feel free to post any questions brother, and we all can throw some suggestions your way