The sense of pain can be reduced in several ways, including the body's own production of endorphins. Feeling pain is, well, painful. Wouldn't you be better off if you could just eliminate pain? The answer to the question of whether you would be better off without a sense of pain is a resounding no.
This situation actually occurs in some people. One of these is a condition called peripheral neuropathy, in which many neurons such as pain receptors in the peripheral nervous system die or become inactive due, for example, to vascular problems associated with diabetes. Loss of pain sense in parts of the body can also be the result of certain strokes and types of brain damage.
People with peripheral neuropathy tend to injure themselves without knowing: They burn themselves while cooking, break bones during routine physical activity, and develop asymptomatic skin lesions that are ignored until they become serious infections. The sense of pain is necessary to prevent harm to the body.
The loss of feeling in a limb is so disabling that people with sensory peripheral neuropathy are effectively paralyzed in that limb, refusing to use it, even if the motor neuron circuitry is actually intact.