Hello you can consult me for better understanding and management of your problem

Your backache seems to be meachanical and postural. But more history is required. For now you can go for tab paracetamol 500 mg whenever you have symptoms or use ficlofenac/menthol gel for local application. Start doing some spinal exercises. If it occurs during periods,  start consulming more water and go for walking during ypur menstruating days. For exercises that may help you the maximum, you can consult me online.

Need detailed history and evaluation

Your pain can be because of your posture or it can be due to less fluid intake or it can be due to some deficiency.. drink plenty of fluids, regular excercise, and if your symptoms persist u can do these tests.. CBC, VITB12, VIT D ..