Breast lumps while breastfeeding are often caused by issues with latching or ineffective milk removal, which can lead to clogged ducts. It is highly recommended that you consult a lactation consultant to assess your baby's latch and ensure you are draining the breast properly during feeds. While some NSAIDs like ibuprofen are generally considered safe while breastfeeding, you should always verify the dosage and appropriateness with your own physician before starting a regular medication regimen.