There are 2 common pain spots for practitioners of zazen: the knees and the back. In my case my back dominates the pain register.
I've talked to a lot of Zen practitioners including Zen monks and I've gotten answers that tend to vary from the macho "sucking it up" approach to maybe you should try a nice comfortable chair.
My approach has been one of exploration and a search for the Middle Way:). Given the importance of zazen in Zen practice I have always been surprised at how little basic instruction is given to the physical posture. It tends to get addressed briefly and then there is a quick transition to the breathing and the awareness of incessant thinking.
I have found that my thinking relaxes the more I can find an acceptable position. It is hard to imagine extended sitting ever being pain-free but the goal of my exploration was to move the pain from a 12 on a scale of 1-10 to somewhere in the 3 to 5 range.
I have had 2 injuries that are clear contributors to my back pain problem. In the next few blogs I'll describe my injuries and the different approaches, tips and tools I have found along the way to gain a balanced posture that supports my zazen. If anyone has other techniques they have tried please share them.
Friendly bows, _/|\_