In any type of flange (and any brand), it's unavoidable for the sides of the nipple to touch the sides of the tunnel because most nipples will swell to fill the available space. But too much swelling puts pressure on milk ducts making it harder for the milk to flow. That's why we find that people get the most milk most comfortably by using the smallest size they can fit in easily to minimize swelling.
From your answers (but without having seen closeup photos of your nipples), it sounds like the pain you're having is from friction from movement in the tunnel and I do definitely see lubrication in the tunnel. I know you didn't use any to pump but any kind of lubrication used on nipples at any time of the day results in the oil absorbing into the deeper layers of the skin, which takes 3-5 days to work all the way out. When pumping the silicone flanges during that time, the oil comes up enough to release your nipples from the tacky inside surface designed to hold elastic tissue, allowing it to move against the textured surface creating friction, but there's not enough oil to protect the nipple from the friction, increasing the risk of blisters and wounds.
When using our silicone flanges, lubrication should be either always used or never used, depending on which of the two reasons you need them:
To control elasticity (stretching too far that closes off milk ducts)
When used to control elasticity, lubrication must be eliminated completely so the tacky silicone can hold the nipples in place to keep the milk ducts open. It can take 3-5 days for lubrication to work its way out of the deeper layers of your skin. Once there's no lubrication left, only the very end of the nipple will move during pumping so there's no friction and you're totally comfortable. If you see more than the end of the nipple moving, we'll need to look for sneaky ways you're still getting lubrication that's allowing friction.
Here's a list of known lubrication sources to check
As a smaller size flange
If you don't need to control for elasticity, you can eliminate friction by using just a little edible oil like coconut or olive oils (too much and the flange gets too slippery). Dish soaps like Dapple and Babyganics or any with an anti-spotting ingredient will leave a lubricating film on silicone that can also help but may make the flange fall out of the bottle adapter too easily.
