Discomfort was for all of 5 seconds while they were held down, not really from the actual snip, I think. The frenulum that was snipped was very thin for all my children. There was the most blood loss on my third which the lactation consultant (she's also a gp) wiped away and I fed my son straight after. He looked confused during the feed to be honest lol. It was a different sensation for him. I'm glad I've had it done for all of my children but the improvement took a long time.
My first sons tie was done at 2 weeks. There was no obvious problem with feeding, however I had it done anyway. His feeding did not show improvement as such because he always had an adequate latch.
My second daughter I had done at 9 weeks old. Her feeding was very poor. She would not have any suction and would just ride my letdown. Thankfully I had an ample supply. Her improvement was not noticeable until perhaps 16 weeks old. This may have coincided with her being able to take a bigger latch as she grew bigger.
My second son did not have a noticeable tie as it was grade 3. It was done at 8 weeks. The lactation consultant who did it advised me that my son had a really high bubble palate which contributed to his poor latch (which is common with children with grade 3 and 4 ties) . I agreed, but she said there is still a "snap back" when he sucks so snipped as much that was non sub mucosal. She said to give it a few weeks before I saw improvement and if I needed to have the release lasered, to contact her. We had issues especially when I was engorged but as my supply regulated his feeding improved dramatically at 15 weeks old. Thankfully.
The pain really is minimal, but I does depend on your child. The exercises are difficult as you are basically rubbing on a wound. My son hated it. I'd imagine this would be far more painful if with a laser.