I've only ever done two biceps injections, with tren, once in each arm.
I didn't like it. It just felt "wrong" for some reason. The first time, in the left biceps, I hit it with a 1" 25g, and a split second after I got the pin all the way in, my arm started twitching involuntarily at the elbow. I got that to stop, aspirated, and completed the injection, but I was constantly aware of the small lump of oil in my arm, until it dissipated.
The next day I hit the right biceps with a 5/8" 25g, and while I didn't have the complications I did with the first one, it was still uncomfortable.
I suppose that the discomfort would go away with repitition. Maybe.