There could be various reasons for your calf muscle pain
Low levels of VIT D,VIT B12,calcium,potassium etcPeripheral artery disease
Deep venous thrombosis
Restless leg syndrome
You must consult a diabetologist
and get investigated thoroughly for the above mentioned causes.
Treatment would depend upon finding the cause.
Keep your blood sugar levels,blood pressure levels and serum lipid levels under meticulous control.
Keep doing regular exercises.