Dear lybrate-user Your pain
seems to be related to your posture
.Hormonal changes during your menses may make it worse. I would advise the following -
1. MRI of the Lumbar spine to rule out any disc herniation or other spinal conditions. 2.Back strengthening exercises like the Bhujangasana ,avoid the exercises when you have severe pain. Go for regular brisk walks but avoid jumping or running and high heels.
Take a diet
rich in calcium like milk, eggs and green leafy vegetables .Take half an hour of sun exposure to improve your Vitamin D levels. Hope this helps.