Low pain tolerance? I don't think so. Tolerance for pain is more of a mental thing, sometimes you consciously choose to withstand pain.
A low pain treshold, on the other hand, might be. A nervous system could be different/damaged and thus a person might not feel pain as easily, or feel it too easily.
Edited 1 time - Last edited at 14:19:00 15/03/2014 by Samius
It's more of a symptom than a condition. However, it can be a symptom of a wider condition.
Fibromyalgia is a disorder where you have a heightened response from your pain receptors when pressure is applied to your body. Having "low pain tolerance" (e.g. flinching when you're touched) is a common symptom of the disorder.