Joint and ligament looseness is fairly common in the months after delivery because of hormonal shifts, and breastfeeding increases your body's
calcium and
vitamin D needs. That combination can sometimes show up as clicking or popping around the knee.
Next Steps
Please keep taking your prescribed supplements as advised, and get the knee and the muscle lump checked in person by an orthopaedist, since a physical exam is needed to know what's actually causing it.
Health Tips
If the clicking comes along with pain, swelling, or the lump grows in size, please don't wait and get it looked at sooner.