You have very low Vit D. And the back miscles become weak with time either due to being bed ridden or due to lack of use/overuse because of taking care of the baby.
The foot pain seems to be due to plantarfascitis which occurs in the, sue to the inflammation in the cushion like structure present in the heel and pain aggravates when you start walking after a long rest. And decreases after short period of walking.
Next Steps
Go to a physiotherapist.. Ultrasonic therapy +IFT +Heating therapy+some strengthening as well as stretching exercises will be helpful for sure.
Health Tips
At home.. Rest +hot water fomentation +pain killer gel +no long sitting /standing /travelling /walking /driving +no cold exposure to the painful parts +no long travelling +no weight lifting +forward bending+correct posture (sit tall) +move your foot back & forth at every two hours interval+dont hang the foot/keep it elevated.