Rob, the first time I ever had a cramp, it was in my calf muscle, was back in 1981 after a weightlifting training session. That was the first time and the last time I had a debilitating muscle cramp. I was 16 at the time, and I was given an advice back then that I'm going to share with you right now. Hey Fadi (Rob), go to your nearest chemist and get yourself some K-Mag tablets. K stands for potassium and Mag stands for magnesium.
I don't take K-Mag now, but I always ensure my magnesium level (and electrolytes) in general are always at an optimal level..., with true salt (I prefer Himalayan salt) is always part of these group.
Happy to recommended certain brands of magnesium for you if you wish me to, as certain carriers of magnesium are better than others, namely the Malate and glycinate carriers, with the malate being excellent for fibromyalgia.