The pressure and pain of needle is entitled to individuals.
Some really scare of needles, no matter how slight, they get anxious about it.
Some have problem with ticker and longer needles.
And some has no feelings over needles.
My experience, needles do pressure the flesh and entering a liquid inside your arteries and muscles. So there would some feelings. Itches, little pain and sometimes burning. Slighter needles are better, it happens quick and you barely would feel anything. Ticker needles obviously feels little bit more pressurized. But generally, needles aren't a big deal at the end. Even we scare of them. If we work on ourselves and stay strong and face it, we'll see it's nothing! It just come and go before you know!