Hi
Thanks for your query
Welcome to HCM
As per symptoms you described it seems that
You may have had restless leg syndrome or leg/calf cramps
Restless leg syndrome is a disorder in which there is an urge or need to move the legs to stop unpleasant sensations
Being diabetic you are at risk of having it
Night time Leg or calf pain/cramps are muscle spasm of un known origin
The cause of your leg pain may be –electrolyte imbalance, uncontrolled diabetes, heavy day time exertion et
You should try—stretch exercise ,warm water massage ,plenty of fluid and salt,
Good rest and sleep, vitamin E and calcium supplementation
Side effects of diaform (metformin) are-
Disturbance to the gut ,Nausea ,Vomiting ,Diarrhoea ,Abdominal pain ,Loss of appetite

Hi,
Welcome to HCM,
You are long standing diabetes and taking treatment metformin 500 mg 3 times a day.
Leg pain is possible due to various causes mostly due to neuropathy please get investigated for neuropathy which most likely cause ,vascular changes should be seen with peripheral Doppler study. other possible cause is side effect of metformin due to lactic acidosis.,Some neurological radiculopathy due to spine problem should be investigated.
If it is due to neuropathy B12 supplements and drugs which control neuropathic pain will give you relief.
If cause is drug then treatment with insulin and stopping metformin will let us know if it is due to drug.
Please also keep your blood sugar level to optimum level which also help to reduce progression of neuropathy.
I hope once your cause of pain diagnosed it can be treated easily.
Take care
Good Luck.