Anak, that sounds painful talaga, especially pag repetitive ang movement like that! Best thing is to check with your doctor kung ano ang safe while breastfeeding, maraming options na pwede but dosage at type really depends sa individual, so hindi kami dapat mag-assume. In the meantime, a few of us moms swear by ice packs, rest, at inaangat namin ang leg kapag sitting para hindi ma-strain pa; one of my friends also did physical therapy exercises which helped a lot sa knee aches niya.