Mild back pain for 1-2 days, then 2wks later both hamstrings and calves had less tone, though other muscles are the same is this due to herniated disc?

Doubtful. It does not sound like this should be due to a ruptured disc. I am not sure what you mean by less tone, however. A ruptured disc usually causes severe leg pain or weakness in one or both of your legs. Seek medical attention if you are concerned.