newly mom and breastffeding noticed lump in my left breast

Hi,
Welcome to ehealthforum,
If you are breastfeeding your baby, the breast lump that you describe could suggest possibility of presence of cyst, infected lobule, breast abscess, galactocele, fibroadenoma, lipomas, fibrocystic disease, mastitis etc. Most breast lumps that develop during pregnancy and lactation are benign but occasionally women do develop breast cancer. Any lump that develops should be taken seriously whether the woman is pregnant or not. The exact cause can only be made out after careful examination and further evaluation. Visit your doctor/gynecologist at the earliest for thorough examination and further evaluation to look for the underlying cause. Mammogram or ultrasound scan, and tumor marker tests done will help to rule out/predict chances of cancer. You can try with warm compresses, use of heating pad, gentle massage, etc to alleviate the pain. Nurse your baby frequently and vary the positions to allow for pressure on different ducts (to help with complete emptying of the ducts). Make sure your bra is giving you good support.
Take care.