If running is ur passion do not take this pain lightly visit some sports physiotherapist immediately for diagnosis of the source of pain. www drrajivmehta com will help u further.

Hi this is Dr Hitin Mathur, orthopaedic surgeon from Fortis C Doc Hospital, New Delhi. If you develop pain while running, it could arise because your leg compartments ie spaces in which your leg muscles are contained may be tight and due to muscle edema, compartment pressures increase leading to pain. A decrease blood supply to legs, low vitamin D or varicose veins could also be a cause. So you need to get yourself examined by an orthopaedic surgeon to find the cause.

It may be due to muscle sprain or due to vitamin D deficiency. Better to get check once