are you supposed to feel the pumping when pumping?

[HaveIGotPoosForYou]

I have bought a ameda lactaline and can't feel the pumping motion barely. Is this normal and if not, what might be causing this?

Thanks. :)

Oh and had a bit come out but it was only 1oz.

I think it must be it's too tight/not tight enough.

How do I know what flange my breasts should have?