You are doing such a great job I think the advice about giving it time is good, and also second Traveller's suggestion to try using a different hold to see what happens. Sometimes babies don't like lying on one side - possibly due to something being out of alignment from birth. Other times they find the flow too fast or too slow on one side. It could also be that your nipple points in a different direction on that side - most us of are not quite symmetrical LOL! Sometimes a tweak to the way you are holding the baby can make all the difference. Changing the position or having a good LC help you with positioning and attachment could work wonders. And if none of the ideas work, there is absolutely no problems with continuing to use the shield for as long as you need to. In most cases babies latch on well without it after the first few weeks, especially when they are already feeding without it on one side.

All the best with it!