Ensure that you maintain an appropriate posture while working or sitting or walking....Take frequent stretch breaks and drink lots of water...Discontinue using pillow while sleeping straight...Do not lift heavy objects, especially after bending down....Eat a healthy wholesome meal which should satisfy your minerals and proteins requirement...take over the counter pain medications.. Consult nearest orthopedic surgeon they will do the needful.

Back pain is common in pregnancy due to relaxation of ligaments. Have her sleep on a hard mattress. She could be having muscle spasm. She can take paracetamol for pain and massage the area. It will be worthwhile to see a orthopaedic surgeon to confirm the cause. Avoid lifting weight