Earlier, I linked to a site with a counterscript to use against telemarketers. Now comes the ultimate response, convincing the bastards you don't exist. By using the three tone sound that you hear when you get a non-working number at the beginning of your answering machine message, the dialing machines will mark your number as dead. Full Instructions for this are provided along with the sound file you need (sit.wav).
Note: According to an article in the latest WIRED, you only need to put in the first tone, not all three. Use your sound recorder program to edit the wav file.
I have found it helpful to do the stretching exercises my physical therapist recommends. Do some core strengthening exercises, such as the ones highlighted at The Mayo Clinic. By keeping your core strong, your back won't put itself in a position to cause that sciatica pain you are having.