Back Problem
 

I've herniated the same disk 3 times in the past year. Does anyone have any inflight back stretches that could help ease some of the pressure if needed?

There doesn't sound like there is much left there to herniate....:)
I have two bad discs and am in the same boat.
When I'm in a cockpit that is big enough, I actually get out of my seat every two hours if possible for a couple minutes. Lean against the galley and stretch my calves. Then grab a foot and pull on the quad a little bit. My doc doesn't recommend bending over and touching the floor as it is worse than the benefit. I carry a peice of rope/band in my bag to lay on the floor, hook it over my foot and pull my leg up to 90* from the floor or more if I can.
In the seat if I'm stuck (i.e. Lear Jet 45), I'm screwed on the stretching, but I can do the kegel type strengthening deal with my abs. Tighten up the abs like you are doing a sit up and hold for 10 seconds. (remember to breathe!) then relax.
Sometimes the only thing that helps is beer and a hot tub.
Good luck.

Sounds good I'll give it a shot!......no pun intended