Your symptoms sound like my first cycle. For me it turned out my gear had ethyl oleate in it(check your vial). Its used because it allows higher concentrations of test/ml to stay in solution without crystalizing. Some people don't react well to it, much pain and swelling, this is not a normal reaction to intramuscular injections.
For the next cycle I used gear without EO, no pain like the first cycle.
Check your vial to see the concentration of benzyl alcohol, it shouldn't be more than 2%. 1% seems pretty standard these days. Higher amount are known to cause PIP.
Like some of the other guys have suggested, warming the steroid vial before injecting can help.If the gear is higher than say 250mg/ml Test E or C, then the steroid powder might not have fully dissolved, can cause pain. Heating will cause it to go back into solution, but it also might crystalize again whilst its in the muscle, still get PIP.
You can still get PIP from some compounds like Test Prop, it feels like a small bruise when touched. It can be painful but not so much that it interferes with how you feel on a day to day basis, or stop you from doing a workout. Pain usually goes in 2-3 days. You can also get PIP from a rough injection, but once again small bruising, not a major intense pain.
Some people also have no go areas for injecting. For me its the quads, so I don't bother using it as a site, nearly always hurts to inject and pip no matter the substance. No swelling and extreme pain/stiffness that I got with EO though.