Best injection spot for high concentration test?

Only been doing dorsal glutes and can’t sit normal for a few days after injection lol. Using 1.5in 25g needle to inject. Was wondering if delt injection might be less painful with insulin pins? Or maybe I should inject .33 ML of test just 3 times per week so I get the full ML. My test is 400mg/ML I’m positive gear is real. It’s just the fact that it’s super concentrated. And I also have a bunch of muscle knots in my glutes so maybes that’s the reason

Idk guys need help lol