There are various video explanations about pain and low pressure. (low barometric pressures).

We have one done at a TV studio somewhere on this forum.
But I can't find it now.

This is a close second illustrating that when pressures go down,
things tend to swell up.

http://www.physics.org/interact/phys...ows/index.html

Of course what happens on a small scale is not visible to us, but perhaps does impact sensory nerves.

Just about every forum we have here that deals with pain issues,
reports posts where people have more pain when the barometric pressure falls. In Europe doctors even consult the weather for their
pain patients.