Hello RichardNY:
The ability to alter bodily systems which are automatic or parts of the autonomic nervous system (heart, lungs) in a very direct way can be achieved using physical techniques of precisely this type.
Whether I stick electrodes on my body in order to get an audio feedback to my physical techniques/efforts is unimportant. Can we change our physical tension? Can we increase the blood flow more generally, or to a specific body part for a given purpose? Can we through specific physical positioning thereby become aware of specific muscles which we unconsciously contract, tighten...? Can I through deeper breathing reduce directly my blood pressure
If the answers to any of those questions is yes, then finding the practice(s) to achieve these ends are numerous. My particular bent and preference would be via assorted originally asian cultural practices but there are many techniques perfectly valid in the western methods and presentation.
Tai Chi Ch'uan, Hatha-Yoga, Karate-do. All approach tension, and its necessary reduction in different ways, and slightly different time frames. Introspection, physical self-awareness is a positive thing and biofeedback, a fine tool for exploring that,,,
What kind of pain are we discussing?
Stuart