Yep, induced labour is often more painful because your body is working harder at it from the git-go, rather than getting a more gentle run-in.
Probably has much more to do with how much pain you have, than baby size.

For me - my first was 8lb10, second was 9lb13 & was the best labour & birth by far - third was 8lb12 & DD2 was 10lb8 - hers was a painful birth, but I was on my back (not where I wanted to be) & I think that had as much to do with it as her size.