Different people are going to experience leg pain differently. Many people get low on potassium, others on magnesium, and some even on calcium, when they start low carbing. Especially in the warmer weather.

Try liberally using Lite Salt on your food (but check the taste before you use too much).

You can also buy magnesium supplements.

Possible that something like Pedialyte electrolyte replacement may help, but I don't know the sugar content of those fluids.

For me, it's always potassium. More lettuce. No table salt, and cut back on the "salty" snacks like pork rinds.

Good luck.