About This Answer
A meditator asks whether tension, tightness and headaches during sitting mean too much meditation. Ajahn Dtun explains that such symptoms come from over-focusing on the meditation object, and advises a right balance, neither too tight nor too loose, which leaves the mind light, relaxed and conducive to concentration.
When tension arises, he suggests setting the object aside and taking a few long, deep breaths, following each all the way in and out. If the tension clears, take up the object again; if not, stop for that sitting. Developing mindfulness and concentration is trial and error at first, but endurance matters: giving up whenever tension appears means the mind never becomes peaceful.
He compares it to a woodcarver making ten figures. The early pieces come out poorly, they improve over time, and only the tenth resembles what was intended, yet none of the earlier attempts was wasted. Reaching concentration likewise requires much trial and error.