What Is The Best Thing To Do For A Hamstring...cold

what is the best thing to do for a hamstring...cold or hot . Is hamstring behind the thigh right pass the knee. I was told that drs. cannot do much for hamstrings ....is that true. my calf is continually tight also. How can I prevent this? I walk and do line dancing. I have not been stretching before or after. What are the best stretches.