Hi. I had delivered a baby boy in June 2016. My knees and lower back is paining lot since two months. I am breastfeeding also started solid food to my baby. I am taking calcium, iron also. I did vitamin d test and reports are showing low. so doctor gave me injection and gave vitamin d tablets which I will have to take once in a week. Whenever I walk or stand up my knees pain a lot. Please reply what could be the reason for paining so much?