I'm experiencing nipple soreness in the evening during cluster feeding. I can get through an hour total on each side before the soreness becomes too much and I turn, I become frustrated. My 4 week old cluster feeds over a 4-6 hour period with very short breaks. I don't have any discomfort during the day and his latch is good. I do have and use a silicone nipple shield but I've heard mixed things. I only introduce the shield when the pain is too much. We've had no problems with refusing breast or weight gain. Am I making things worse by using a shield or is this an acceptable short term sanity saver until we get through this phase?