Whats up with my calf ?

I have a really bad pain in my calf muscle, it hurts if touched and if i'm lying on that leg it hurts and when i lift it up from that position it hurts again. It feels like touching a bruise kinda pain. Yet if i stretch the muscles such as sitting down leg out in front and try to touch my toes, the pain goes away hugely, and helps alot. A. What is wrong with my calf ? B. Why does the stretching work 100x better than ice or heat treatment ?