How many moms felt the ring of fire with epidural? I did with my first hurt so bad! Did they not put it in correctly??

Has anyone used the narcotic in the IV for pain? Does it work fully even if you’re 7-8 cm??? I took it with my first 5 times I was 3-4cm but the last 2-1 weren’t helping anymore I was wondering so with my second I know better when to use it so it can work! I want to labor at home much as I can and once I go to hospital I want to be able to walk and do different positions hold off on epidural much as I can