Brief Answer:
Rest; physiotherapy; medication and evaluation...

Detailed Answer:
Hi,

Without a clinical examination it is difficult to predict the back pain. Further you have not specified the exact location of ache - is it the neck, upper back or lower back. I presume it's the lower back.
Furthermore is the pain localised to this region or spreads down to the groin / legs. What is the severity of pain on a scale of 1 to 10 (with 10 being the most severe pain you ever had)?
Does it hurt to bend / turn?
Is your daily activities affected by this pain?

Answers to aforementioned questions might help me to some extent understand the pain; but not completely to locate the cause.

In the meantime, I will recommend you starting pain medications such as diclofenac or etoricoxib with thiocolchicoside. You get combination brands. You can ask your local doctor. Adequate rest and avoiding strenuous physical activity will also help. If needed, you can try physiotherapy under guidance of a physiotherapist.

Hope this helps.

Regards

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