Take care - I got a small knot in my calf muscle a couple of years ago. One day I was rushing to my work and I heard a "bang" and my leg was suddenly in agony. The calf muscle had ripped. I thought that I had been shot.
It took a few weeks to repair but the first few days was really bad, I was on crutches.
Quinine is great for cramp but the tablets are only available on prescription. Tonic water is full of quinine so if you can stomach drinking the muck then that should help.
deep heat rub in then five minuets after run on the spot for 5 minuets to warm the muscle further then stretch very slowly for 10 seconds wait 10 seconds for 2 mins then see how you feel tomorrow, you can also try to massage it when it is warm.