My first had silent refulx, and my second just reflux, but severe. Things that helped me were:

Feeding with him "sitting" up rather than lying down (your lc might have shown you how to do this)
Wearing in carrier after feeds so he is upright
Feed as much as possible (had to do this with my first as he would throw right back up)

I don't think you should have to express that many hours a day, it can't be a good quality of life for you and you need the rest! I would just keep putting her on the boob, you can try nipple stimulation yourself too.

You're doing a really good job.