How many ultrasound scan during pregnancy? Anyone got poked too hard during scan?

I’m under subsidised route at kkh, I’ve had about 3 scans now, week 6, week 12, and week 20 which is recently. The week 20 scan hurt so much as the nurse was trying to get all the arms, legs and kidney and heart measurements. And she also poke too rough to my stomach and shake/slap my belly a few times to make my baby move. Is that normal? She seems like middle age lady from China. Now I’m scheduled to have another scan after 4 weeks, but I’m scared it will be too rough again.