I recommend ACEFORCE MR SOS

Zerodol-TH 4 is not a good choice while breastfeeding because it contains thiocolchicoside, which is not recommended in lactation due to potential risk to the baby. Even though aceclofenac and paracetamol are generally considered safer, the muscle relaxant component makes this combination unsafe to use without medical advice. For back muscle spasm during breastfeeding, paracetamol alone is the safest first option, and ibuprofen is usually considered compatible with breastfeeding if needed. Along with medicines, try local heat, gentle stretching, adequate rest, and avoiding sudden bending or lifting. If pain is severe or persistent, please consult your doctor to prescribe a breastfeeding-safe alternative.

If baby is 6 montb old, than you can