I am worried because I experience severe pain in my legs and calves from time to time.

I am worried because lately I occasionally experience severe, cramp-like pain in my legs, specifically my calves. At first, I thought it was just from standing for long periods, but recently, when it gets severe, the pain feels like a leg cramp and is so intense that it wakes me up from sleep. I am not sure if it is simply a circulatory issue or if it is a symptom caused by an underlying health problem. I try to keep the area as warm as possible and massage it before going to sleep, but I am concerned because the cramp-like sensation occurs once in a while during the night.