When i visit my gynecologist for my regular checkups, the speculum is usually difficult to insert and might hurt, so it's hard to insert anything unless i'm aroused, so my gynecologist asks me to stimulate myself or asks to do it. is that normal?

It would be inappropriate for a doctor to "stimulate" you. A doctor's exam should include the speculum insertion to visualize your cervix and take a sample for the pap smear, and a bimanual exam involving using a finger or two in the vagina and a hand on your lower abdomen to feel your pelvic organs. To improve your vaginal capacity or elasticity, you can use a vaginal dilator at home.