The majority of women (around 80% or so) can only orgasm from clitoral stimulation, so that's not strange in the least. It's less common to be able to orgasm from penetration alone. So the need for clitoral stimulation is not a quirk so much as the standard. The clitoris is the female analogue to the penis, so it makes sense that stimulating it would be the most common route to orgasm!
As for the G-spot, that varies from woman to woman. Many greatly enjoy the stimulation, while others are indifferent or dislike it. Some can have G-spot orgasms, some never do. Nothing odd there.
As for pain during penetration, that could be a couple of different things. If it's bumps to your cervix that hurt, then you need to be gentler with your toys and/or tell your partner that they're pushing a bit too hard. Otherwise, penetration usually shouldn't be painful if you're relaxed and aroused enough. It could just be that you need extra lubricant or need a bit more foreplay, though there are medical conditions that can result in painful penetration. If it's not about cervical bumps, and you're fully relaxed, aroused, and sufficiently lubricated and are still feeling pain, then I'd suggest asking your doctor.
