Brief Answer:
Growing pains

Detailed Answer:
Hi
Thanks for your query.

It may be growing pains that children and pre-teens experience during growth spurts. Cramping, achy pains happen in legs during afternoon and evening time or even during night. We can help by massaging the legs or giving pain killers like ibuprofen when the pain is bad.

Sometimes such pain may happen due to nutritional deficiencies of calcium and vit D. In nutritional deficiencies, run a blood test to confirm deficiency and give supplements accordingly.

Another cause maybe due to excessive running or other sports activities.

If it persists then its worthwhile to visit an orthopedic surgeon for further evaluation.

Hope it helps. Let me know if I can assist you further.
Dr Vaishalee

---